Krystyna Koziol
email: k.a.koziol@gmail.com

Roland Kallenborn

Zhiyong Xie

Catherine Larose

Andrea Spolaor

Elena Barbaro

Jan Kavan

Daniel Kępski

Anna Nikulina

Krzysztof Zawierucha

David Pearce

Luke Cockerton

Adam Nawrot

Filip Pawlak

Paulina Pakszys

David Cappelletti

Page

Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere (HERMOSA)

Keywords: aerosol, atmospheric pollution, monitoring coordination, aerobiology, dust deposition, contaminants of emerging Arctic concern (CEACs)

de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 3

Popular science summary

Highlights  Air impurities were measured in Svalbard, from sulphur to pollen, already before 1980s

 Air quality monitoring is spatially uneventhe Ny-Ålesund hub needs to be supported by other regular sites  Methods of impurity measurement show similarities which can be exploited for better problem solving

Summary

Many characteristics of atmospheric air are measured in Svalbard, including levels of chemical pollution, dark dust connected to soot, and living organisms, but most of these studies happen in Ny-Ålesund. First air monitoring was initiated as early as 1970s, and multiple atmospheric components have been added to the monitoring over time (especially since 2010; in early 2000s a few parameters from Hornsund have joined the regular programme). Newer types of contaminants are being discovered and measured in Svalbard. Methods for detecting simpler substances and particles have been established for a long time, while certain complex chemicals and small living organisms are more difficult to capture and study. Laboratory and field equipment upgrades help improve understanding of the Svalbard environment. In this chapter, we find that collecting information on many characteristics of the air at the same time helps solve long-standing scientific questions in Svalbard, such as the origins of pollution in the Arctic air and the future of Arctic atmosphere in the changing world. This is especially important since the Arctic is changing fast, both due to the planet warming and the shift in local people's activity from mining to services, e,g. tourism.

Recommendations

 Researchers should agree on important parameters of the atmospheric composition to be measured in at least three places across Svalbard (we propose Ny-Ålesund, Longyearbyen and Hornsund, and parameters: black carbon (soot), the greenhouse gas methane, inorganic ions, pollen and novel organic chemicals).

 Change in time (between seasons and years) of a few of such parameters should be measured simultaneously, to better study the influence of human activity and climate change.

This would be easier to study in the future if organic chemical analysis was saved for future searches of novel chemicals (that is, an electronic sample bank was founded).

 Ny-Ålesund is the best place to study how such parameters change between sea level and mountain tops, but in other places it should be tested, too, with shorter experiments. Methods at various locations need to be harmonised and laboratories compared for robust results.

Photos or popular science graphics/figures

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Introduction

Atmospheric pollution research and monitoring in Svalbard occupies a significant position in pan-Arctic research on priority pollutants (AMAP 2016(AMAP , 2017)), providing observations of their long-range atmospheric transport [START_REF] Iversen | Arctic air pollution and large scale atmospheric flows[END_REF][START_REF] Hung | Atmospheric monitoring of organic pollutants in the Arctic under the Arctic Monitoring and Assessment Programme (AMAP): 1993-2006[END_REF]. Atmospheric research in Svalbard has been increasing in diversity and magnitude in the recent years, with more comprehensive long-term observational efforts and numerous short-term intensive field experiments.

Coordination of the research and scientific exchange in terms of common sampling and analytical protocols, joint data analysis, publications, and related planning of future research has growing potential. It presents two advantages: lowers the environmental footprint of researchers coming to Svalbard (by reducing the numbers of people necessary to collect samples for various impurities) and allows to see a bigger, interconnected picture of environmental processes.

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In this chapter, we collect information from various sources on the state of the research and monitoring of priority pollutants and other impurities in the atmosphere over Svalbard, bridging the chemical, biological and supportingly physical monitoring efforts. By atmospheric impurity we consider any kind of substance that is dispersed in the atmosphere, whether in gaseous or particulate form. The definition encompasses molecules of various sizes and chemical composition, to biological cells and small organisms, referred to as aerial plankton. Among physical properties of the atmospheric aerosol, we mention mainly the AOD as a basic parameter monitored in Svalbard, however it is elaborated on elsewhere (e.g. in the LOAD-RiS chapter). Unfortunately, it is impossible to list every short-term dataset from a campaign conducted in Svalbard, hence we only strive for a representative overview with a focus on long-term monitoring programmes. The opportunities for harmonising several types of measurements are sought in this work, and the distribution of measurements across Svalbard is both an opportunity and a hindrance, hence the first iteration of the problem is divided by geographical locations. Direct monitoring of the atmospheric impurities is also closely connected to their deposition in precipitation, and hence we mention here the efforts in precipitation sampling which may lead to synergy with aerosol or air sampling, yet we have to restrict considerations of the topic to such cases alone (excluding, for example, the literature on ice cores collected in Svalbard).

In the past, there have been a few chapters of SESS Reports showing a particular fraction of the vast topic of atmospheric impurities [START_REF] Gallet | Snow research in Svalbard: current status and knowledge gaps[END_REF][START_REF] Malard | Microbial activity monitoring by the Integrated Arctic Earth Observing System (MamSIOS)[END_REF][START_REF] Petkov | Observations of the solar UV irradiance and ozone column at Svalbard[END_REF][START_REF] Viola | The Lower Atmosphere above Svalbard (LAS): Observed long term trends, small scale processes and the surface exchange[END_REF][START_REF] Gilardoni | Atmospheric black carbon in Svalbard (ABC Svalbard)[END_REF][START_REF] Mazzola | Probing of the Vertical Structure of the lower Atmosphere over Svalbard (ProVeSAS)[END_REF][START_REF] Sipilä | Multidisciplinary research on biogenically driven new particle formation in Svalbard (SVALBAEROSOL)[END_REF][START_REF] Singh | Microplastics in the realm of Svalbard: current knowledge and future perspectives (MIRES)[END_REF][START_REF] Traversi | Arctic haze in a climate changing world: the 2010-2020 trend (HAZECLIC)[END_REF][START_REF] Petkov | The extreme Arctic ozone depletion in 2020 as was observed from Svalbard[END_REF]). In the interest of efficient information processing, we will only refer to topics previously described in SESS reports to the extent which is necessary to understand the potential for harmonisation between the already described and other atmospheric components. The same approach is taken with the parallel chapters in this report on mineral dust (SVALDUST) and AOD measurements (LOAD-RiS). Due to the focus on measurement harmonisation and the best potential to do so for lower tropospheric, ground-based measurements, we will narrow our focus to this kind of experiments and monitoring programmes.

2 Overview of existing knowledge

Existing monitoring and available datasets

Atmospheric impurity monitoring in Ny Ålesund

Ny Ålesund has an unparalleled position in the Arctic and Svalbard atmospheric impurity monitoring, holding two main facilities with an elevation difference of 425 m (Gruvebadet at 50 m and Mt. Zeppelin at 475 m asl), and several facilities dispersed in its vicinity (Figure A1). It offers a unique opportunity for harmonised studies of atmospheric impurity differences with elevation (within and beyond the boundary layer) and between multiple impurities. For example, a recent study [START_REF] Song | Understanding Sources and Drivers of Size-Resolved Aerosol in the High Arctic Islands of Svalbard Using a Receptor Model Coupled with Machine Learning[END_REF]) has explored the sources of atmospheric particles in Ny-Ålesund with machine learning, showing the importance of secondary aerosol in cloud condensation processes and predicting non-linear changes in aerosol composition with temperature changes (resulting from climate change).

The earliest regular monitoring work at Ny Ålesund has been conducted by NILU, starting as early as 1989 (for SO 2 and SO 4 2-measurements), although earlier short-term studies have been conducted

there, e.g. in 1980-83 on organochlorine POPs by [START_REF] Oehme | The long range transport of polyclorinated hydrocarbons to the Arctic[END_REF]. Studies of CEACs from Svalbard testify also to the transport, persistence and impacts of these chemicals in the Arctic [START_REF] Hao | Atmospheric concentrations and temporal trends of polychlorinated biphenyls and organochlorine pesticides in the Arctic during 2011-2018[END_REF][START_REF] Li | Organophosphate esters in Arctic air from 2011 to 2019: Concentrations, temporal trends, and potential sources[END_REF].

A large part of the atmospheric impurity research at Ny-Ålesund is nowadays located also in the Gruvebadet atmospheric laboratory (GVB), about 1 km away from the main settlement. The GVB is dedicated to the study of the atmospheric composition and the atmosphere-cryosphere interaction.

The laboratory is equipped with several instruments dedicated to aerosol studies (see positions 12 -29 in section 6 table / Table A2 in Appendix). The accessible roof holds an installation of both sampling heads and full samplers (Figure 1). Several continuous measurements are performed at GVB to fully characterise the aerosol composition within the planetary boundary layer during the entire year and with dedicated experimental campaigns. Specialty areas of GVB laboratory include sizesegregated chemical and optical analyses of particulate matter (PM10), including trace elements, WSOC, and BC forms, microplastics, additives, plasticizers and other CEACs, as well as INP properties, all performed with state-of-the-art analytical techniques. Multi-decadal results of eBC (see section 2.2 for a definition of eBC) are available in Svalbard from Zeppelin; since 2010, these data have been integrated into the measurements at the Gruvebadet laboratory (cf. [START_REF] Gilardoni | Atmospheric black carbon in Svalbard (ABC Svalbard)[END_REF].

Continuous monitoring of the optical (scattering and absorption) and physical (dimensional distribution)

properties of the in-situ aerosol using semi-automatic instrumentation (nephelometer and SMPS and APS absorption photometer) are conducted in collaboration between Italian institutions running GVB and AWI (Germany), INAR (Finland), the University of Stockholm (Sweden), the NCSR "Demokritos" (Greece) and KOPRI (Republic of South Korea). Recently (in 2021), a measurement campaign of particle fluxes using the eddy covariance technique was conducted, collecting measurements of momentum flows and ultrafine particles with a sonic anemometer and a condensation meter CPC.

Flow measurements of dimensionally segregated particles were conducted through the use of an optical counter OPC. A passive sampler for dry deposition of aerosol, and a "Cyclone" sampler collecting spores and pollen, compliment the programme at this supersite.

The GVB facility is also used to study the atmosphere-cryosphere interaction (in tune with a SESS Report recommendation by [START_REF] Gallet | Snow research in Svalbard: current status and knowledge gaps[END_REF], through a parallel programme of snow monitoring (for wet and dry deposition), showing the role of snowpack as a chemical sink of emissions from rock weathering, forest fire, marine and biogenic emissions, and anthropogenic contaminants, such as BC, showing strong snow to air evaporation for fluorotelomer alcohol and fluorotelomer acrylates [START_REF] Xie | Neutral Poly-/perfluoroalkyl Substances in Air and Snow from the Arctic[END_REF]. For atmosphere-cryosphere interaction studies, a weekly sampling of the entire snowpack has been adoptedby snow pit approach, with a vertical resolution of 10 cm. Snow is then analysed to quantify the concentration of the elements and compounds (at CNR-ISP), the BC loading (at NPI) and to characterise the microbial community (at Universite De Lyon\CNRS). Snow density and stratigraphy data support the chemical data interpretation, and an automated nivometric station works near the GVB site since 2020. It is worth mentioning that at GVB, several measurements have been intergrated into one sampling protocol, described partially in the studies using the data collected there [START_REF] Scalabrin | Amino acids in Arctic aerosols[END_REF][START_REF] Zangrando | Molecular Markers of Biomass Burning in Arctic Aerosols[END_REF][START_REF] Turetta | Water-soluble trace, rare earth elements and organic compounds in Arctic aerosol[END_REF][START_REF] Turetta | A Year-Round Measurement of Water-Soluble Trace and Rare Earth Elements in Arctic Aerosol: Possible Inorganic Tracers of Specific Events[END_REF][START_REF] Feltracco | Free and combined L-and D-amino acids in Arctic aerosol[END_REF][START_REF] Feltracco | Interannual variability of sugars in Arctic aerosol: Biomass burning and biogenic inputs[END_REF]Feltracco et al. , 2021b, a), a). The currently developing project BETHA-NyÅ (RiS ID 11924) aims to further harmonise aerosol measurements at GVB and Zeppelin, as has been postulated in a SESS Report by [START_REF] Traversi | Arctic haze in a climate changing world: the 2010-2020 trend (HAZECLIC)[END_REF].

Other land-based atmospheric impurity research in Svalbard

Besides the atmospheric measurement hub at Ny Ålesund, the main air impurity screening sites in Svalbard are located in Longyearbyen, Barentsburg, and Hornsund, however studies on specific topics may be encountered in other locations, such as Petuniabukta. One of the earliest monitoring sites in the Norwegian Arctic (including Svalbard) was Bjørnøyathe inorganic compounds in atmospheric air and aerosol have been measured there since 1977 (SO 2 in atmospheric air, http://ebas.nilu.no/). Important discoveries at the time have been based on this station functioning, e.g. [START_REF] Iversen | Some statistical properties of ground level air pollution at Norwegian Arctic stations and their relation to large scale atmospheric flow systems[END_REF] showing the meteorological mechanism of long-range atmospheric transport causing winter/spring pollution maxima. The measurements in Bjørnøya were phased out in 1989.

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In Longyearbyen, a strong focus of atmospheric impurity research was on local and regional pollution.

A fully equipped sampling observatory has been established on the roof of UNIS, with several high volume air samplers (TISCH, Cleves, OH, USA, Type TE-1000BL, US EPA TO-A4, TO-9A). Further campaign-based studies were conducted at the former Aurora observatory in Adventdalen, and in collaboration with SvalSat on the adjacent Plateau mountain. During the past years, in Longyearbyen, POPs and novel CEACs have been detected in gaseous and/or particle phase during research projects (including novel PFAS, PCBs and PAHs and their major transformation products).

The research conducted in Longyearbyen has been instrumental in documenting the transition from a coal-mining-based community to a settlement relying mostly on services as an income source, with both sources contributing to local air pollution. Coal mining has been present in Longyearbyen (and Svalbard in general) since the early 1900s when John Munro Longyear established the first mining infrastuctures in Adventdalen [START_REF] Westby | Store norske Spitsbergen kulkompani 1916-1945[END_REF][START_REF] Kvello | Store norske Spitsbergen kulkompani: om arbeide i en politisk bedrift p Svalbard 1970-2000[END_REF]. Since then, five major locations across Svalbard had large coal mining infrastructures established and operated (Table A3 in Appendix). After the Norwegian government decided to abandon coal mining on Svalbard (in 2017), other business activities like services, municipality, research, education, building and maintenance, as well as international tourism, have replaced coal mining as professional areas in Svalbard [START_REF] Avango | Imprints on the Resource Landscape : The Long History of Mining in the Arctic[END_REF].

Today, around 3000 inhabitants are living and working in Svalbard, mainly in Longyearbyen (2400)

and Barentsburg (400). All settlements in Svalbard are isolated infrastructures: life-supporting services such as heating, electric power, water supply and waste handling need to be provided on-site. In addition to high costs of infrastructure operation, settlements in Svalbard have a significantly higher ecological footprint per inhabitant compared to mid-latitude locations, where infrastructure is shared.

An earlier report by the Norwegian Environmental Agency concluded that Svalbard man-made CO 2 emissions (produced by ca 3000 people = 0.06% of the total population) accounted for ca 1% of the total Norwegian CO 2 emissions in 2009 (Vestreng et al., 2009). Hence, the local emissions are important to control -also to minimize exposure risk for local populations (e.g. to CEACs).

For two decades now, Svalbard settlements were comprehensively investigated for local pollution.

Transportation and emissions from gasoline-fuelled engines are an important local contamination source on Svalbard. Shipping, the operation of heavy-fossil-fuel-driven vehicles (e.g. lorries), and private transportation (cars, snowmobiles) contribute significantly to the local pollution profile. [START_REF] Reimann | Severe aromatic hydrocarbon pollution in the Arctic town of Longyearbyen (Svalbard) caused by snowmobile emissions[END_REF] reported on the emission of VOCs in Longyearbyen, especially BTX, from snowmobile exhaust. Elevated BTX levels were attributed to the extensive use of two-stroke engine snowmobiles in November -June. Those BTX emission levels were similar as in a medium size European city, like Zürich (400 000 inhabitants). Also for PAHs, elevated air concentrations were confirmed to come from fossil-fuel-driven engines, both in and around Longyearbyen. A variety of local sources such as a local fuel station, the coal power plant and various municipal installations were confirmed. Unlike BTX, PAHs are environmentally stable contaminants and hence were subsequently found in surface soil along major snowmobile tracks near Longyearbyen.

PAHs are relevant local pollutants, and coal-fired power plants both in Longyearbyen and Barentsburg are identified as their major local source. A recent comprehensive study investigated the emission profile and the rapid atmospheric transformation process for PAHs [START_REF] Marquès | Concentrations of polycyclic aromatic hydrocarbons and trace elements in Arctic soils : A case-study in Svalbard[END_REF][START_REF] Drotikova | Polycyclic aromatic hydrocarbons (PAHs) and oxy-and nitro-PAHs in ambient air of the Arctic town Longyearbyen, Svalbard[END_REF][START_REF] Drotikova | Polycyclic aromatic hydrocarbons (PAHs) and their nitrated and oxygenated derivatives in the Arctic boundary layer: seasonal trends and local anthropogenic influence[END_REF]. Air samples from three locations, at increasing distances from the source (0 -8 km from the power plant), were investigated for PAHs and their major transformation products (oxy-and

Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 12 nitro-PAHs). Seasonal profiles have thus been described for the PACs: during polar day, rapid photochemical transformation eliminates nitro-PAHs, while oxy-PAHs are less affected.

In the past years, a variety of new organic pollutants were identified as local contaminants in Svalbard (AMAP 2017; [START_REF] Kallenborn | Pharmaceuticals and personal care products (PPCPs) in Arctic environments: indicator contaminants for assessing local and remote anthropogenic sources in a pristine ecosystem in change[END_REF]). Among CEACs, PFASs were found to be directly emitted from Svalbard installations, mainly at the local airports (Longyearbyen, Ny-Ålesund, Sveathe fire fighting training locations) and local waste dumps [START_REF] Skaar | Elucidation of contamination sources for poly-and perfluoroalkyl substances (PFASs) on Svalbard (Norwegian Arctic)[END_REF][START_REF] Ali | The fate of poly-and perfluoroalkyl substances in a marine food web influenced by land-based sources in the Norwegian Arctic[END_REF]. Elevated levels of PFAS in the local food webs were confirmed both in Ny-Ålesund and Longyearbyen. Recently, a study on surface snow revealed the presence of novel ultra-short PFASs in the vicinity of Longyearbyen (Foxfonna glacier). Here, the photochemical transformation of long-chain precursor PFAS led to elevated levels of TFA and TFMS in surface snow. TFA was also identified in drinking water in Longyearbyen (Nödler, pers. comm.), proving the importance of PFAS emission screening.

In Barentsburg, aerosol measurements started in 2011 [START_REF] Sakerin | Preliminary results of studying the aerosol characteristics of the atmosphere in the region of Barentsburg, Spitsbergen[END_REF][START_REF] Golobokova | Studies of atmospheric aerosols in the Russian Arctic regions[END_REF].

Since Barentsburg. After the introduction of filter system on Barentsburg power plant in 2012, the total ion concentrations were halved by 2016, and slightly increased after [START_REF] Sakerin | Seasonal and interannual variability of aerosol characteristics in arctic settlement of Barentsburg (Spitsbergen, 2011-1017)[END_REF]. Generally, concentrations increase in winter-spring period and slightly drop in May-June, with sea spray as a main source of aerosol throughout the year and the local influence of coal mining and power plant exhaust more prominent during the polar night [START_REF] Golobokova | Chemical composition of the near-surface atmospheric aerosol in Barentsburg (Spitsbergen) based on the long-term observations[END_REF].

RPA "Typhoon", North-West branch (Saint-Petersburg) ground-based monitoring programme includes the analysis of atmospheric aerosol for 16 PAHs, PCBs and trace metals, since 2002 [START_REF] Demin | The state and trends of environmental pollution in the places of economic activity of Russian enterprises on Spitsbergen archipelago (Barentsburg and adjacent territories) for the period 2002-2010. RPA "Typhoon[END_REF]. Apart from direct measurements, method development and intercalibration exercises with NILU were conducted. Samples have been collected twice a year in spring (March) and late summer (August) by a multichannel sampler PU-4EP (Russia) simultaneously on three filters AFA-HA-20

(acetate cellulose fibrous material with electrostatic effect, 20 cm 2 ) at three sites in Barentsburg and outside the settlement (Demin et al., 2011, E. Yaeski, pers comm). The methods of sampling and analysis remain unaltered for the whole period of observations.

The Governor of Svalbard, in collaboration with the Norwegian Environmental Protection Agency (Miljødirektoratet), commissioned a Svalbard-wide survey on potential local sources of PCBs in 2007 [START_REF] Lundkvist | PCBs in Svalbard: status of knowledge and management[END_REF]. Virtually in all settlements on Svalbard, elevated PCB concentrations were

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found in the local environment; decommissioned and defect technical equipment (like transformers)

was identified and removed for proper destruction. This first survey noted the paucity of information on PCB contamination from Russian settlements and hence a dedicated campaign for mapping PCB contamination in Barentsburg and Pyramiden was initiated [START_REF] Evenset | Norsk og russisk overvaking av PCB-forurensning ved bosettinger pa Svalbard: Sammenligning av felt-og analysemetoder og resultater[END_REF]. The authors concluded that although local emissions were considered high, the majority of Svalbard PCB pollution stems from decades of atmospheric long-range transport.

In southern Spitsbergen, long-term monitoring of several atmospheric pollution parameters is carried out in the PPSH (at Hornsund). PPSH is the longest operating site in the AERONET network in Svalbard, providing, i.a., continuous cloud-screened observations of spectral AOD since 2004. Aerosol studies have been complemented with ceilometer data since 2017. Extended measurements of aerosols in the atmosphere were conducted there in the years 2009-2015, when Raman lidar was operational [START_REF] Pietruczuk | LIDAR at Polish Polar Station, instrument design and first results[END_REF], detecting the impact of volcanic ash [START_REF] Karasiński | Lidar observations of volcanic dust over Polish Polar Station at Hornsund after eruptions of Eyjafjallajökull and Grímsvötn[END_REF] or wildfires [START_REF] Markowicz | Impact of North American intense fires on aerosol optical properties measured over the European Arctic in July 2015[END_REF]) on the atmosphere of Svalbard. In the spring of 2021, more detailed data on the concentration of the aerosol and its size distribution were collected using the OPS 3330 and NanoScan SMPS 3910 TSI spectrometers.

Chemical composition of aerosol is also monitored at PPSH, however less comprehensively. PPSH is one of the northernmost continuous monitoring sites of radionuclides in the ground-level atmosphere since 2002 (Mysłek-Laurikainen et al. 2006), recently expanded to include EcoGamma environmental gamma radiation monitor. This monitoring additionally provides information on the concentration of dust deposited on the Petrianov filters replaced in AZA-1000 at weekly intervals [START_REF] Burakowska | Concentration of 7Be, 210Pb, 40K, 137Cs, 134Cs radionuclides in the ground layer of the atmosphere in the polar (Hornsund, Spitsbergen) and mid-latitudes (Otwock-Świder, Poland) regions[END_REF]). The measurements have confirmed an influx of radioactive isotopes into Svalbard after the Fukushima nuclear power plant disaster [START_REF] Burakowska | Concentration of 7Be, 210Pb, 40K, 137Cs, 134Cs radionuclides in the ground layer of the atmosphere in the polar (Hornsund, Spitsbergen) and mid-latitudes (Otwock-Świder, Poland) regions[END_REF], which was visible also in Ny-Ålesund [START_REF] Paatero | Airborne fission products in the high Arctic after the Fukushima nuclear accident[END_REF]. Besides this ongoing programme, recent measurements have been The precipitation composition data collected by PPSH, before and after 2004, allowed to characterise rain and snow composition origins (e.g. [START_REF] Pulina | Stratification and physico-chemical properties of snow in Spitsbergen in the hydroglaciological year 1989/1990. -Wyprawy Geograficzne na Spitsbergen. Materiały Sesji Polarnej "Arctic Environment Research[END_REF][START_REF] Głowacki | Physico-chemical properties of precipitation and snow cover in Spitsbergenin winter season 1992/1993[END_REF][START_REF] Głowacki | The physico-chemical properties of the snow cover of Spitsbergen (Svalbard) based on investigations during the winter season 1990/1991[END_REF][START_REF] Burzyk | Comparative chemical characteristics of precipitation in the Hornsund region (SW Spitsbergen) in the years 1993-1994 and 1998-1999[END_REF][START_REF] Krawczyk | Charakterystyka chemiczna opadów atmosferycznych w rejonie Hornsundu (SW Spitsbergen) latem 2000 r. na tle cyrkulacji atmosferycznych[END_REF][START_REF] Krawczyk | Organic compounds in rainfall at Hornsund, SW Spitsbergen: qualitative results[END_REF][START_REF] Kozak | The role of atmospheric precipitation in introducing contaminants to the surface waters of the Fuglebekken catchment, Spitsbergen[END_REF], spatial differences in precipitation chemistry (e.g. [START_REF] Krawczyk | Rain water chemistry at Calypsobyen, Svalbard[END_REF], and the impact of wild fires and longrange transport (e.g. [START_REF] Bryś | Meteorological and orographic conditions of ionic deposition from precipitations and atmospheric depositions in the Hornsund area in the period July 1999 -June 2000[END_REF][START_REF] Głowacki | Long range transport of pollutantsevidences from rainfall chemistry in Hornsund (Svalbard)[END_REF][START_REF] Ruman | The research of the contamination levels present in samples of precipitation and surface waters collected from the catchment area Fuglebekken (Hornsund, Svalbard Archipelago)[END_REF][START_REF] Kozak | The role of atmospheric precipitation in introducing contaminants to the surface waters of the Fuglebekken catchment, Spitsbergen[END_REF][START_REF] Nawrot | Chemistry of snow cover and acidic snowfall during a season with a high level of air pollution on the Hans Glacier, Spitsbergen[END_REF].

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Specific study topics with atypical or sparse spatial representation

Aeolian dust studies in Svalbard, recently renewed after a dormant phase since the 1980s (e.g. [START_REF] Pękala | Morphogenetic processes and cover deposits of nunataks in the Hornsund area (SW Spitsbergen)[END_REF][START_REF] Åkerman | Notes concerning the vegetation on deflation surfaces, Knapp Linné[END_REF][START_REF] Gębica | Symptoms of aeolian accumulation in western Sorkapp Land Spitsbergen[END_REF], are limited to a few sites. Direct observational data exist only for Ny-Ålesund [START_REF] Moroni | Vertical Profiles and Chemical Properties of Aerosol Particles upon Ny-Ålesund (Svalbard Islands)[END_REF][START_REF] Moroni | Local vs . long-range sources of aerosol particles upon Ny-A (Svalbard Islands): mineral chemistry and geochemical records[END_REF][START_REF] Moroni | Mineralogical and Chemical Records of Icelandic Dust Sources Upon Ny-Ålesund (Svalbard Islands)[END_REF][START_REF] Gallet | Protocols and recommendations for the measurement of snow physical properties, and sampling of snow for black carbon, water isotopes, major ions and microorganisms Gauchard PA[END_REF][START_REF] Conca | Source identification and temporal evolution of trace elements in PM10 collected near to Ny-Ålesund (Norwegian Arctic)[END_REF][START_REF] Jacobi | Deposition of ionic species and black carbon to the Arctic snowpack: combining snow pit observations with modeling[END_REF]) Hornsund [START_REF] Migała | Deflation and nival eolian phenomena observed under conditions of congelation in the forefield of the Werenskiold Glacier (SW Spitsbergen)[END_REF][START_REF] Kavan | High Latitude Dust Transport Altitude Pattern Revealed from Deposition on Snow, Svalbard[END_REF][START_REF] Lewandowski | Seeking the Sources of Dust: Geochemical and Magnetic Studies on "Cryodust" in Glacial Cores from Southern Spitsbergen (Svalbard, Norway)[END_REF][START_REF] Spolaor | Investigation on the Sources and Impact of Trace Elements in the Annual Snowpack and the Firn in the Hansbreen (Southwest Spitsbergen)[END_REF]; and Longyearbyen (e.g. [START_REF] Khan | Impacts of coal dust from an active mine on the spectral reflectance of Arctic surface snow in Svalbard, Norway[END_REF][START_REF] Kandler | Differences and Similarities of Central Asian, African, and Arctic Dust Composition from a Single Particle Perspective[END_REF]. Apart from that, there are only two studies from Petuniabukta area, central Svalbard [START_REF] Kavan | High Latitude Dust Transport Altitude Pattern Revealed from Deposition on Snow, Svalbard[END_REF][START_REF] Rymer | Contemporary and past aeolian deposition rates in periglacial conditions (Ebba Valley, central Spitsbergen)[END_REF]. The studies at Ny Ålesund were conducted by ground level active filtering [START_REF] Conca | Source identification and temporal evolution of trace elements in PM10 collected near to Ny-Ålesund (Norwegian Arctic)[END_REF], or vertical profiling [START_REF] Moroni | Vertical Profiles and Chemical Properties of Aerosol Particles upon Ny-Ålesund (Svalbard Islands)[END_REF][START_REF] Moroni | Local vs . long-range sources of aerosol particles upon Ny-A (Svalbard Islands): mineral chemistry and geochemical records[END_REF]; the detailed mineralogical and chemical composition of the aerosol was reported by [START_REF] Moroni | Mineralogical and Chemical Records of Icelandic Dust Sources Upon Ny-Ålesund (Svalbard Islands)[END_REF]. Aeolian processes are also monitored as the deposition of material on snow [START_REF] Khan | Impacts of coal dust from an active mine on the spectral reflectance of Arctic surface snow in Svalbard, Norway[END_REF][START_REF] Gallet | Protocols and recommendations for the measurement of snow physical properties, and sampling of snow for black carbon, water isotopes, major ions and microorganisms Gauchard PA[END_REF][START_REF] Jacobi | Deposition of ionic species and black carbon to the Arctic snowpack: combining snow pit observations with modeling[END_REF][START_REF] Kavan | High Latitude Dust Transport Altitude Pattern Revealed from Deposition on Snow, Svalbard[END_REF][START_REF] Lewandowski | Seeking the Sources of Dust: Geochemical and Magnetic Studies on "Cryodust" in Glacial Cores from Southern Spitsbergen (Svalbard, Norway)[END_REF][START_REF] Spolaor | Investigation on the Sources and Impact of Trace Elements in the Annual Snowpack and the Firn in the Hansbreen (Southwest Spitsbergen)[END_REF]. The only direct deposition of dust was observed by [START_REF] Rymer | Contemporary and past aeolian deposition rates in periglacial conditions (Ebba Valley, central Spitsbergen)[END_REF] with the passive samplers in central Spitsbergen. Quantifying mineral dust deposition remains a challenge due to its large spatial and temporal variability -the measured deposition rates vary, are site-specific, and depend on the method used.

Another sparsely distributed type of measurement across Svalbard is aerobiological sampling.

Aerobiology research is a relatively nascent field in Svalbard -few studies have been published from the archipelago on aerial microbiology and aerial plankton, the transport of pollen and eukaryotic spores, both of local and long-range origin (cf. Figure A1). [START_REF] Johansen | Airborne pollen and spore registrations at Ny-Ålesund, Svalbard, summer 1986[END_REF] revealed pollen, bryophyte and fungal spores in Burkard trap at Ny-Alesund, most of them of local origin.

However, [START_REF] Polunin | ARCTIC AEROPALYNOLOGY: SPORA OBSERVED ON STICKY SLIDES EXPOSED IN VARIOUS REGIONS IN 1950[END_REF] found mostly exotic pollen species for Svalbard including Pinus pollen highlighting the role of long-range transport. In a study on bacterial diversity in the air over Svalbard, biodiversity was found to be similar to other, both polar and non-polar environments. The identification of viable bacteria suggests that living bacteria are ubiquitous in the air around Svalbard [START_REF] Cuthbertson | Characterisation of Arctic Bacterial Communities in the Air above Svalbard[END_REF]. In a 6-month study on the bacterial community composition in the atmosphere at Ny-Ålesund, community structure exhibited seasonal dynamics that mimicked the different stages of bacterial colonization of algal blooms in the surrounding fjords. This highlights the importance of open water as a source of airborne microorganisms (Feltracco et al. 2021a). In a cultivation-dependent study (likely to underestimate the number of live air-borne microorganisms), fifteen fungal taxa were isolated from the air of Longyearbyen ( generating pilot data to determine the potential of such monitoring. Finally, despite the microinvertebrates predominating in faunal diversity of polar regions and playing a pivotal role in matter flow, the majority of studies investigate microinvertebrate transport only by migratory birds, humans or imported soils [START_REF] Coulson | Introduction of invertebrates into the High Arctic via imported soils: the case of Barentsburg in the Svalbard[END_REF][START_REF] Pilskog | Invertebrate communities inhabiting nests of migrating passerine, wild fowl and sea birds breeding in the High Arctic, Svalbard[END_REF]. Few studies discuss passive transport of invertebrates by wind at all [START_REF] Hodkinson | What a wonderful web they weave: spiders, nutrient capture and early ecosystem development in the high Arctic -some counter-intuitive ideas on community assembly[END_REF][START_REF] Coulson | Aerial colonization of high Arctic islands by invertebrates: the diamondback moth Plutella xylostella (Lepidoptera: Yponomeutidae) as a potential indicator species[END_REF][START_REF] Coulson | Aerial dispersal of invertebrates over a high-Arctic glacier foreland: Midtre Lovenbreen, Svalbard[END_REF][START_REF] Coulson | The alien terrestrial invertebrate fauna of the High Arctic archipelago of Svalbard: potential implications for the native flora and fauna[END_REF], and among them, only two test aerial transport empirically [START_REF] Coulson | Aerial colonization of high Arctic islands by invertebrates: the diamondback moth Plutella xylostella (Lepidoptera: Yponomeutidae) as a potential indicator species[END_REF][START_REF] Coulson | Aerial dispersal of invertebrates over a high-Arctic glacier foreland: Midtre Lovenbreen, Svalbard[END_REF].

Atmospheric impurities research from the seas surrounding Svalbard

A complimentary element of atmospheric impurity monitoring in Svalbard is its presence in the seas around the archipelago. While sampling techniques and protocols match those used on land, marine research is tied geographically to cruise routes and thus repeated measurements concern a wider area instead of an exact location of the sampling site. Challenging atmospheric conditions at sea introduce potential measurement hindrance, e.g. the dense fog, strong wind and breaking wave. Oceania, initiated in 1991Oceania, initiated in , continuing between 2001Oceania, initiated in and 2021Oceania, initiated in (2009Oceania, initiated in , 2012Oceania, initiated in , 2015Oceania, initiated in , 2017Oceania, initiated in , 2020Oceania, initiated in , 2021)), crowned with the longest, over one-year cruise of the MOSAiC expedition across the Arctic Air quality monitoring on the sea is especially important in the context of sea-air exchange phenomena. Substantial evidence from observations and modelling shows the impact of climate change on the biogeochemical cycle of POPs and CEACs in the Arctic, pertinent to both the seas and the atmosphere [START_REF] Ma | The influence of global climate change on the environmental fate of persistent organic pollutants: A review with emphasis on the Northern Hemisphere and the Arctic as a receptor[END_REF]. For instance, many legacy POPs have revolatilized into air from water, snow or ice as a concenquence of sea ice retreat and rising temperatures [START_REF] Ma | Revolatilization of persistent organic pollutants in the Arctic induced by climate change[END_REF].

Besides, many CEACs were likely transported with ocean currents and waves from the low and medium latitudes to the High Arctic. The warm Atlantic seawater may bring CEACs such as ionic PFASs, OPEs and PPCPs into the waters surrounding Svalbard and influence their atmospheric levels thorugh air-water gas exchange or sea spray [START_REF] Li | Organophosphate Esters in Air, Snow, and Seawater in the North Atlantic and the Arctic[END_REF][START_REF] Sha | Sea Spray Aerosol (SSA) as a Source of Perfluoroalkyl Acids (PFAAs) to the Atmosphere: Field Evidence from Long-Term Air Monitoring[END_REF]

Sampling techniques and data collection protocols

The liquids and solids dispersed in the atmospheric air (i.e. aerosols, PM) encompass both iorganic and organic chemicals, frequently in mixed particles, particles of specific optical properties, such as BC, and more complex and larger airborne impurities, such as pollen, microplastics, and small living organisms. Some of these substances have closely related aerosol and gaseous forms, e.g. sulphate in aerosol which comes from the dissolution of gaseous SO 2 . With such a variety of analytes, a suite of analytical approaches needs to be employed for their qualitative and quantitative characterisation.

However, since the mode of transport is similar for multiple species of similar molecular or particle size, there can be also found similarities in sample collection approachwhich allow for weekly flask sampling has also been used in trace gas analysis by NOAA CMDL.

Inorganic ionic species in atmospheric aerosol play an important role as source indices [START_REF] Giardi | Size distribution and ion composition of aerosol collected at Ny-Ålesund in the spring-summer field campaign 2013[END_REF][START_REF] Udisti | Sulfate source apportionment in the Ny-Ålesund (Svalbard Islands) Arctic aerosol[END_REF][START_REF] Amore | Source apportionment of sulphate in the High Arctic by a 10 yr-long record from Gruvebadet Observatory (Ny-Ålesund, Svalbard Islands)[END_REF], for example, sodium and chloride are typically originating from sea salt, bromide and iodide depend on the sea ice extent [START_REF] Spolaor | Sea ice dynamics influence halogen deposition to Svalbard[END_REF]. Some of them also play a role in climate forcing [START_REF] Toon | Atmospheric Aerosols and Climate: Small particles in the Earth's atmosphere interact with visible and infrared light, altering the radiation balance and the climate[END_REF][START_REF] Satheesh | Radiative effects of natural aerosols: A review[END_REF], exerting a cooling effect by light reflection and forming reflective clouds (especially sulphate). Their role as CCN is also important [START_REF] Merikanto | Impact of nucleation on global CCN[END_REF]). Since it is relatively easy to determine the concentration of ions, they form a basis for further analyses and have been monitored in Svalbard for a long time. The traditional method of sample collection for the analysis of inorganic ions in air and aerosol includes a combination of denuders (glass and alkaline-carbon-coated) and filters [START_REF] Beine | Three years of springtime trace gas and particle measurements at Ny-Ålesund, Svalbard[END_REF]). The filter pack captured both fine and coarse particulate matter (a Teflon filter, 1-µm pore size)

and acids evaporated from the front filter (a Nylon filter, 1-µm pore size). The analytical technique best suited for the determination of inorganic ions collected by both denuders and filters is ion chromatography. Collection times applied by [START_REF] Beine | Three years of springtime trace gas and particle measurements at Ny-Ålesund, Svalbard[END_REF] were between 12 and 24 hours.

Nowadays, sampling and analysis of inorganic ions remains similar, yet with a large variety of modified Alternatively, copper grids coated with carbon film may be used, combined with a later analysis by electron microscopy (as in Chinese Yellow River Station). NanoSIMS may be used to analyse the composition of individual aerosol particles then [START_REF] Chi | Sea salt aerosols as a reactive surface for inorganic and organic acidic gases in the Arctic troposphere[END_REF]. At GVB, the equivalent of this approach is using nucleopore polycarbonate membrane filters with a 12-stage low volume impactor and analysis by SEM (see also section 2.1.1), which is also a way to study mineral dust composition.

For mineral dust quantification, most sampling protocols are rather individual and depend on the device used (for active sampling procedures). The passive sampling in [START_REF] Rymer | Contemporary and past aeolian deposition rates in periglacial conditions (Ebba Valley, central Spitsbergen)[END_REF] used the standard Marble Dust Collector traps [START_REF] Hall | A wind tunnel study of the particle collection efficiency of an inverted Frisbee used as a dust deposition gauge[END_REF]). An alternative sample collection strategy involves snow cover sampling as a carrier of mineral dust deposition. Usually only the upper layer of snow is sampled to avoid contamination from the ground surface.

Sampling for the determination of metals and metalloids is very similar to sampling for the determination of ions, and sometimes different parts of the same filter are used for both determinations [START_REF] Zhan | Effects of ship emissions on summertime aerosols at Ny-Alesund in the Arctic[END_REF][START_REF] Golobokova | Chemical composition of the near-surface atmospheric aerosol in Barentsburg (Spitsbergen) based on the long-term observations[END_REF], which is an excellent harmonisation example. Analytical methods, invasive and non-invasive, are used to determine the content of metals and metalloids. The invasive method requires wet digestion of the sample, using e.g. nitric acid and microwaves as an energy source. Subsequently, the content determination is performed using inductively coupled plasma mass spectrometry [START_REF] Berg | Temporal Trends in Atmospheric Heavy Metal and Organochlorine Concentrations at Zeppelin, Svalbard[END_REF][START_REF] Demin | The state and trends of environmental pollution in the places of economic activity of Russian enterprises on Spitsbergen archipelago (Barentsburg and adjacent territories) for the period 2002-2010. RPA "Typhoon[END_REF][START_REF] Zhan | Effects of ship emissions on summertime aerosols at Ny-Alesund in the Arctic[END_REF][START_REF] Bazzano | Elemental and lead isotopic composition of atmospheric particulate measured in the Arctic region (Ny-Ålesund, Svalbard Islands)[END_REF][START_REF] Conca | Source identification and temporal evolution of trace elements in PM10 collected near to Ny-Ålesund (Norwegian Arctic)[END_REF][START_REF] Conca | Chemical Fractionation of Trace Elements in Arctic PM10 Samples[END_REF][START_REF] Golobokova | Chemical composition of the near-surface atmospheric aerosol in Barentsburg (Spitsbergen) based on the long-term observations[END_REF][START_REF] Turetta | A Year-Round Measurement of Water-Soluble Trace and Rare Earth Elements in Arctic Aerosol: Possible Inorganic Tracers of Specific Events[END_REF]. This method can also be used to determine the isotope content of e.g. lead [START_REF] Bazzano | Elemental and lead isotopic composition of atmospheric particulate measured in the Arctic region (Ny-Ålesund, Svalbard Islands)[END_REF]. It is also possible to determine the content of the radioisotope 210 Pb using the automatic alpha/beta analyser [START_REF] Paatero | Lead-210 concentration in the air at Mt. Zeppelin, Ny-Ålesund, Svalbard[END_REF]. A non-invasive method is to use XRF [START_REF] Anderson | Characterization of individual fine-fraction particles from the Arctic aerosol at Spitsbergen, May-June 1987[END_REF][START_REF] Shpartko | The SR-XFA Method Used to Determine the Multi-Element Composition of Arctic Aerosols[END_REF]).

Among metals, mercury is of special importance due to its toxic effects. Hg is determined in the air in three forms: GEM, RGM and Hg-P (Gauchard et al. 2005). The most popular GEM determination device is a Tekran gas-phase mercury vapor analyser, which uses the CVAFS technique: the atmospheric air is passed through a gold trap, the gold forms an amalgam with mercury, and after a specified enrichment time of the sample, thermal mercury desorption and final detection as HgO by atomic fluorescence spectrometry is performed. For the other two types of mercury, they must first be isolated from the air stream: for RGM, KCl-coated annular denuder or soda lime trap is used, and for Hg-P, quartz filters are used. The enriched samples can then be analysed using the CVAFS technique [START_REF] Ferrari | Snow-to-air exchanges of mercury in an Arctic seasonal snow pack in Ny-Ålesund, Svalbard[END_REF][START_REF] Osterwalder | Fate of Springtime Atmospheric Reactive Mercury: Concentrations and Deposition at Zeppelin, Svalbard[END_REF]. A detailed description of the repeatability of the method has been made by [START_REF] Aspmo | Measurements of atmospheric mercury species during an international study of mercury depletion events at Ny-Ålesund, Svalbard, spring 2003. How reproducible are our present methods?[END_REF].

BC particles have a unique combination of properties, including strong visible light absorption, being refractory with an aggregate morphology, and insoluble in water and common organic solvents [START_REF] Gilardoni | Atmospheric black carbon in Svalbard (ABC Svalbard)[END_REF]. BC mass concentrations are measured directly by incandescent and thermal techniques or indirectly from absorption measurements using appropriate mass absorption crosssection values as the conversion factor [START_REF] Petzold | Recommendations for reporting "black carbon" measurements[END_REF]. Different terms are used depending on the property being measured. While rBC refers to incandescent measurements, EC is used for thermal techniques and eBC is the term for optical or photoacoustic techniques. Intercomparison of different techniques agrees within a factor of two. The principal measurement technique for BC is based on SP2, using an online laser-induced incandescent method for size distribution of rBC. Total mass concentrations and information on the mixing state of BC (a ratio of BC to total particle diameters) can also be derived [START_REF] Schwarz | The Detection Efficiency of the Single Particle Soot Photometer[END_REF][START_REF] Kondo | Consistency and Traceability of Black Carbon Measurements Made by Laser-Induced Incandescence, Thermal-Optical Transmittance, and Filter-Based Photo-Absorption Techniques[END_REF] [START_REF] Golobokova | Chemical composition of the near-surface atmospheric aerosol in Barentsburg (Spitsbergen) based on the long-term observations[END_REF]. The concentrations of PAHs were measured by a GC-MS (GC with MS detection) Triple Quadrupole system. In the RPA "Typhoon" programme, less typically, 16 PAHs concentrations were determined with a HPLC with fluorescence and diode array detectors. PCB analysis was performed with a GC-ECD (Demin et al., 2011, E. Yaeski, pers comm).

A challenging topic for the sampling and analysis techniques is CEACs, due to variety of the encountered substances, new substances being added to the catalogue, and their relatively low concentration levels. As the concentrations of CEACs in Arctic air are usually at picograms to nanograms per cubic meter (pg/m 3 to ng/m 3 ), suitable sampling and pre-concentration techniques are essential to match the sensitivity of the analytical instruments. Active air sampling is performed with a HVS equipped with a GFF or QFF for collecting atmospheric particles (cutoff points vary), and the solid adsorbents, e.g. Amberlite XAD-2 resin, PUF or PUF-XAD-2 combination for the gaseous phase [START_REF] Röhler | Non-target and suspect characterisation of organic contaminants in Arctic air --Part 2: Application of a new tool for identification and prioritisation of chemicals of emerging Arctic concern in air[END_REF][START_REF] Röhler | Non-target and suspect characterisation of Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 69 organic contaminants in ambient air -Part 1: Combining a novel sample clean-up method with comprehensive two-dimensional gas chromatography[END_REF]. Cellulose nitrate membrane filter (pore size: 1-5 µm) is used to trap microplastics in the air. The sampling of CEACs is typically compatible with the former POPs collecting programmes.

Passive samplers (PAS) have been also deployed to monitor the background level and annual trends of POPs and CEACs in Svalbard [START_REF] Li | Organophosphate esters in Arctic air from 2011 to 2019: Concentrations, temporal trends, and potential sources[END_REF]. Sampling media include PUF discs, XAD-2 resin and SPMDs. The PASs are cost-effective, simple in operation, and could be deployed anywhere, e.g., on a glacier or in remote sites without power supply. The application of PAS provides additonal data -from more locations.

Many other organic compounds are also screened in Svalbard by NILU, as can be ascertained from the http://ebas-data.nilu.no database. Such compounds were collected by a HVS (besides selected POPs, including PFAS, also carbohydrates such as levoglucosan, mannitol or sucrose, and other substances, e.g. bisphenol A or triclosan; also total OC), PASa PUF plug (PAHs, OCPs, PCBsa campaign in 2006), steel canister (chosen alkanes and alkenes), glass flask (selected alkanes), and adsorbent tube (selected aldehydes and ketones). A distinct set of methods is dedicated to aerobiology, while the basic collection mechanism resembles that for other particulates (Feltracco et al. 2021a). Aerobiological sampling methods involve impaction, impingement, membrane filtration (Figure 3) or drop plate mechanisms, which have been extensively reviewed in [START_REF] Griffin | Observations on the use of membrane filtration and liquid impingement to collect airborne microorganisms in various atmospheric environments[END_REF]. Although efforts have been made to establish standard methodologies [START_REF] Pearce | Aerobiology Over Antarctica -A New Initiative for Atmospheric Ecology[END_REF][START_REF] Dommergue | Methods to Investigate the Global Atmospheric Microbiome[END_REF][START_REF] Jensen | Seasonal Variation of the Atmospheric Bacterial Community in the Greenlandic High Arctic Is Influenced by Weather Events and Local and Distant Sources[END_REF], no single ideal method exists. For example, microinvertebrates passively transported by wind are still collected by classical techniques, unchanged in decades. Each methodology has advantages and disadvantages (Table 1) Table 1: Typical aerobiology sampling methods.

Harmonising Environmental

Method Advantages Disadvantages

Membran

Contributions to interdisciplinarity

An integral part of this chapter is connecting the chemical, biological and supportingly physical measures of atmospheric impurity loading, and certainly more work at this interface is warranted. The analysis of geographical distribution of atmospheric impurity measurements in Svalbard shows the most likely location for interdisciplinary studies in the Ny-Ålesund hub, as co-siting multilple measurements offers vast opportunities for the improved understanding of the Arctic environment as a whole. The internal harmosation of measurements at Ny-Ålesund is already underway. Emerging disciplines, such as aerobiology or CEACs is likely to be enhanced there in the future. However, other locations offer a further insight into iinterdisciplinary problems, for example Longyearbyeninto screening the human impact during the change of predominant activity type in the area. Furthermore, climate-induced changes in spatial patterns and seasonality in air-impurity-related parameters need to be studied at more than one site to be comprehensively understood, and the Arctic is likely to face multiple non-linear changes (e.g. [START_REF] Song | Understanding Sources and Drivers of Size-Resolved Aerosol in the High Arctic Islands of Svalbard Using a Receptor Model Coupled with Machine Learning[END_REF]. The air impurity interactions with climate are likely to be at the forefront of interdisciplinary issues in Svalbard since multiple components of the atmospheric aerosolof various origins, and both chemical and biologicalcan act as CCN and INPs [START_REF] Varutbangkul | Hygroscopicity of secondary organic aerosols formed by oxidation of cycloalkenes, monoterpenes, sesquiterpenes, and related compounds[END_REF][START_REF] Möhler | Heterogeneous ice nucleation activity of bacteria: new laboratory experiments at simulated cloud conditions[END_REF][START_REF] King | Investigating primary marine aerosol properties: CCN activity of sea salt and mixed inorganic-organic particles[END_REF][START_REF] Abbatt | Overview paper : New insights into aerosol and climate in the Arctic[END_REF]. Furthermore, both direct and indirect impact of aerosol upon radiation and precipitation components of climate has been noted [START_REF] Toon | Atmospheric Aerosols and Climate: Small particles in the Earth's atmosphere interact with visible and infrared light, altering the radiation balance and the climate[END_REF][START_REF] Satheesh | Radiative effects of natural aerosols: A review[END_REF][START_REF] Merikanto | Impact of nucleation on global CCN[END_REF][START_REF] Burgos | A global model-measurement evaluation of particle light scattering coefficients at elevated relative humidity[END_REF][START_REF] Allen | Climate and air quality impacts due to mitigation of nonmethane near-term climate forcers[END_REF], and the climate properties change air quality. Interdisciplinary aspects, such as impacts on cryosphere and ecosystems, are inherent in atmospheric impurity studies [START_REF] Boy | Interactions between the atmosphere, cryosphere, and ecosystems at northern high latitudes[END_REF], as are the well-known connections to human health, social science and economy [START_REF] Ipcc W | The Physical Science Basis. Summary for Policymakers IPCC W (2022a) Climate Change 2022. Impacts, Adaptation and Vulnerability. Summary for policymakers IPCC W (2022b) Climate Change 2022. Mitigation of Climate Change. Summary for Policymakers[END_REF](IPCC , 2022a, b), b).

Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 21

Unanswered questions

Within each field of atmospheric impurity research, there remain unanswered questions. For example, researchers investigating mineral dust still ponder the origin of the deposited material, especially whether it is local or long-range transported (e.g., [START_REF] Moroni | Local vs . long-range sources of aerosol particles upon Ny-A (Svalbard Islands): mineral chemistry and geochemical records[END_REF][START_REF] Moroni | Mineralogical and Chemical Records of Icelandic Dust Sources Upon Ny-Ålesund (Svalbard Islands)[END_REF][START_REF] Conca | Source identification and temporal evolution of trace elements in PM10 collected near to Ny-Ålesund (Norwegian Arctic)[END_REF][START_REF] Kavan | High Latitude Dust Transport Altitude Pattern Revealed from Deposition on Snow, Svalbard[END_REF][START_REF] Lewandowski | Seeking the Sources of Dust: Geochemical and Magnetic Studies on "Cryodust" in Glacial Cores from Southern Spitsbergen (Svalbard, Norway)[END_REF]. Shrinking glaciers are expected to expose more mineral dust sources locally [START_REF] Zawierucha | Micromorphological features of mineral matter from cryoconite holes on Arctic (Svalbard) and alpine (the Alps, the Caucasus) glaciers[END_REF][START_REF] Schuler | Reconciling Svalbard Glacier Mass Balance[END_REF][START_REF] Geyman | Historical glacier change on Svalbard predicts doubling of mass loss by 2100[END_REF][START_REF] Rymer | Contemporary and past aeolian deposition rates in periglacial conditions (Ebba Valley, central Spitsbergen)[END_REF].

Altitude effects are also of concern, as are seasonal changes. Specifically for CEACs, questions arise about their degradation products and their environmental fate.

We believe that the parallel monitoring of multiple impurities would accelerate research progress towards solving such questions, since information provided by various impurity contents will be more comprehensive and thus more likely conclusive. chosen CEACs (e.g. PFAS due to known sources in Svalbard). Such measurements should be performed with consistent methods and be subject to interlaboratory checks. Co-timing of measurements (and matching their time resolutions) at these stations will also be necessary. Regular measurements will allow detecting also the changes in seasonal phenomena due to climate change.

Recommendations for the future

For several atmospheric impurities, three sites across Svalbard are insufficient to detect the spatial differences, especially in bulk atmospheric deposition, which is both more varied and more relevant to the impact on the terrestrial system than pure atmospheric concentrations. For such variables, field campaigns can be used to supplement the existing data, be it with the use of PAS or snow as a natural deposition medium. Impurities we recommend here are: mineral dust, CEACs with an established negative impact on the terrestrial ecosystem, BC and aerobiological parameters (the deposition of pollen, and DNA studies of microbial communities).

The altitudinal transect in Ny Ålesund between Mt. Zeppelin and Gruvebadet should remain in operation, if possible with unified protocolsconsistent with SESS recommendations by [START_REF] Sipilä | Multidisciplinary research on biogenically driven new particle formation in Svalbard (SVALBAEROSOL)[END_REF] and [START_REF] Traversi | Arctic haze in a climate changing world: the 2010-2020 trend (HAZECLIC)[END_REF]; shorter-term experiments on altitude differences in impurities concentration in the atmosphere and their deposition would be beneficial elsewhere [START_REF] Viola | The Lower Atmosphere above Svalbard (LAS): Observed long term trends, small scale processes and the surface exchange[END_REF].

Unified or highly comparable measurement methods are desired, which has already been postulated for BC [START_REF] Gilardoni | Atmospheric black carbon in Svalbard (ABC Svalbard)[END_REF] or microplastics [START_REF] Singh | Microplastics in the realm of Svalbard: current knowledge and future perspectives (MIRES)[END_REF] wide sampling strategies (consistent with the conclusions of [START_REF] Petkov | The extreme Arctic ozone depletion in 2020 as was observed from Svalbard[END_REF]. Therefore, a longterm experiment with parallel collection with different sampling protocols at one site is proposed here.

A sample bank should be designed for CEACs, in the form of non-targeted chemical analysis recording (with high resolution GC or LC-MS techniques), since there is a possibility of discovering further chemicals in a future re-analysis of such data and thus detecting in past samples the CEACs only discovered in the futureand studying their temporal trends, testifying to the changing human impact in the Arctic, resulting e.g. from the diversion of shipping routes or increased tourism.

Broadening the spectrum of measured properties also applies as a prospective research area in aerobiology as more in-depth characterisation of the gene pool in the aerial microbiome becomes possible. Functional links with the environment are also an important concern for future aerobiology studies (new recommendations compared to [START_REF] Malard | Microbial activity monitoring by the Integrated Arctic Earth Observing System (MamSIOS)[END_REF].

Finally, the breadth of existing data, not all of which is fully available (FAIR-compliant), drives the last recommendation to make the existing and future datasets findable, accessible, interoperable and reusable to facilitate solving complex scientific problems connected to atmospheric impurities through collaboration.

6

Data availability

No. on the map (Fig. A1) Tables Table 1: Typical aerobiology sampling methods. Here, the whole section 6 should be placed in tandem with the map in Figure A1, and the section

Dataset

Method Advantages Disadvantages

Membran

Caption 1 :Caption 3 :

 13 A collection of instruments monitoring air composition (and pollution) atop Gruvebadet laboratory roof in Ny-Ålesund. Ny-Ålesund is the main place in Svalbard for air monitoring, with two main stations -Gruvebadet near sea level and Zeppelin mountain top. (Photo: Marco Casula) Caption 2: The environmental chamber of the Polish Polar Station Hornsund, also with a few instruments sampling the air on its roof. Regular measurements of aerosol in Hornsund started in 2002 (Photo: Krystyna Koziol) Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 5 One of the air-sampling instruments, used for persistent and newly discovered pollutants (Photo: Roland Kallenborn) Caption 4: For air sampling for microorganisms, there are a number of instruments available. Key questions for a researcher are: a) a filter size which captures bacteria, b) relatively high flow through the instrument to study DNA, c) the ability of the instrument to cope with the Arctic environment, d) a convenient power source (e.g. a battery) and e) best if there are other users in the scientific world.

Figure 1 :

 1 Figure 1: Overview of the instruments placed atop Gruvebadet atmospheric laboratory roof. (Photo: Marco Casula)

  made in Hornsund within the scope of short-term projects Sea-snow POPs (RiS ID 11108) and HiLDA (RiS ID 11195) since 2019 (Figure2), to determine organic compounds concentration in the atmospheric air at PPSH and to characterise mineral and antropogenic compounds in atmospheric particulate matter.Since 2004, monitoring of the chemical composition of precipitation (rain and snow) has been carried out in Hornsund (FigureA1, see also section 6). Samples are collected: 1) ~500 m north of PPSH (from a HDPE precipitation collector, daily) after each rain or snowfall; 2) on glaciers (Hansbreen until 2019; Ariebreen since then) after each snowfall near the ablation poles (into PE bags); 3) in an elevation transect from the seashore to the summit of Fugleberget, irregularly (into PE bags). All physico-chemical analyses are carried out in the PPSH chemical laboratory. After pH, conductivity and HCO 3 -titration measurements, samples are filtered (on 0.45 μm cellulose membrane filters) and analysed for the major ion composition using ion chromatography (now a Methrom 930 Compact IC).

Figure 2 :

 2 Figure 2: The environmental chamber facility of the PPSH, with various sampling heads exposed on the roof in the spring 2019; a rainfall collector is located 100 m eastwards from there (Photo: K. Koziol)

  . MOSAiC was the first year-round expedition into the central Arctic exploring the Arctic climate system drifting with the sea ice across the central Arctic from September 2019 to October 2020, for example launching radiosondes onboard. AWI's polar research aircraft and UAVs played an important part in atmospheric investigations throughout MOSAiC (Mazzola et al. 2020; Griesche et al. 2020).

  protocols. For example,[START_REF] Teinilä | Aerosol chemistry during the NICE dark and light campaigns[END_REF] used polycarbonate films and a sequence of membrane filters with two types of impactors in their NICE campaign (at Ny-Ålesund). In Barentsburg, samples were collected on a four-stage filter pack. The direct accumulation of aerosol took place at the first PTFE filter (0.8 μm pore size; Golobokova et al 2013; Chernov et al 2016). Three other filters, chemically pre-treated (EANET 2003), collected gases (filter 2: nitric acid, filter 3: sulphur dioxide, hydrochloric acid, filter 4: ammonia). Similarly, Park et al. (2017), Becagli et al. (2019) and Jang et al. (2021) used quartz filters to analyse sulphate and MSA concentration (at GVB). All the above studies Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 17 used a variation of 18 MΩ water extraction and ion chromatography as determination technique. The variety of employed filter materials allows to harmonise ion analysis with a different particulate impurity monitoring, using filterpapers dedicated to that purpose.

  Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 19 Given the diverse techniques and configurations developed for monitoring POPs and CEACs in Arctic air, sampling artifacts often occur along with the technique design, sampling material, and air-sampling interval, in particular: breakthrough, microbial and photo degradation, and equilibrium or nonequilibrium states regarding passive sampling (Bohlin-Nizzetto et al. 2020; Li and Wania 2021; Hao et al. 2021). The concentrations of certain POPs and CEACs could be underestimated by 30-95% (Melymuk et al. 2014), which might override their seasonal variations and mislead the assessment of their environmental fate and related risk. Therefore, the current challenge is to validate sampling approaches with a focus on the POPs and CEACs through interlaboratory comparison to achieve comparability of air impurity measurements in the Arctic. The detailed information on methodologies for air sampling, chemical analysis, data management and QA/QC were described in the literature and annual reports (NILU 2021).

  selecting the right one will depend on the research question. Recent developments in this regard include work by[START_REF] Ferguson | Bioaerosol biomonitoring: Sampling optimization for molecular microbial ecology[END_REF], who evaluated airborne recovery efficiencies using filtration and liquid impingement and found filtration using polycarbonate filters to give the best recovery, with impingement recommended for shorter duration of sampling.[START_REF] Luhung | Experimental parameters defining ultra-low biomass bioaerosol analysis[END_REF] investigated DNA extraction efficiencies from filters and found direct extraction (by placing sampling filter into extraction kit) to result in underestimating total cell numbers. Instead, they suggested a two-stage approach: first removing biomass from the filter, then re-filtering onto a smaller, thinner membrane. Total bacterial count can be measured by growing cells on agar and counting the total number of CFUs and fluorescence microscopy on filters (combined with staining via a universal DNA stain such as DAPI, or a 16S-rRNA-specific probe such as EUB338) and molecular methods[START_REF] Mayol | Resolving the abundance and air-sea fluxes of airborne microorganisms in the North Atlantic Ocean[END_REF][START_REF] Cuthbertson | Characterisation of Arctic Bacterial Communities in the Air above Svalbard[END_REF]. With the development of molecular sequencing methods (PCR, Sanger resp. Illumina sequencing), with improvements in microscopy, cell culture, and sampling methodology, along with modern sensitive sensors detecting changes in air compositionnew possibilities opened up in quantifying the abundance, diversity and composition of several biological constituents in the air.

Figure 3 :

 3 Figure 3: For air sampling for microorganisms, there are a number of commercial options available. Key considerations are: a) direct collection or a filter size of 0.2 μm to capture bacteria, b) maximum flow rates for DNA yield, c) the ability ability to cope with the Arctic environment, d) a convenient power source (battery or generator) to enable long sample runs and e) preferably many users to provide data for comparison elsewhere. Pictured is one such example, the SAS Air Sampler as deployed in the field. (Photo: David Pearce)

  These concerns and open questions are shared on a principal level with other atmospheric impurities, and they can be summarised as: the question of changing origin (what is the proportion of local to long-range sources?), changing seasonality (how do seasonal patterns in impurity concentrations change?), and unknown effects of altitude. Additional concern is a question of climate impact of atmospheric impurities in such changed conditions, through light scattering in the atmosphere, precipitation changes and albedo (surface reflectivity) effects. In aerobiology, increasing temperatures in the Arctic along with an increasing number of tourists spur a question about invasion of Svalbard by non-native pollen and spores.

For a harmonised picture

  of spatial distribution of key atmospheric impurities across Svalbard, we recommend to establish regular measurements of a basic set of variables at ground-based stations, which are logistically available and represent a different level of local human impact (proposed here: Longyearbyen, as the main settlement, and Hornsund, as a relatively remote site with year-round staff). These are also AERONET sites, already measuring AOD. The proposed set of key impurities includes: BC (due to its climate impacts and a large uncertainty in deposition patterns; cf.[START_REF] Zdanowicz | Elemental and water-insoluble organic carbon in Svalbard snow: a synthesis of observations during 2007 -2018[END_REF]; CH 4 (due to climate effects and potential local sources), inorganic ions (simple aerosol source markers), pollen (to track the colonisation of Svalbard by new plants), and finally

  Figures and tables

Figures

  Figures

Figure 1 :Figure 2 :

 12 Figure 1: Overview of the instruments placed atop Gruvebadet atmospheric laboratory roof. (Photo: Marco Casula)

Figure 3 :

 3 Figure 3: For air sampling for microorganisms, there are a number of commercial options available. Key considerations are: a) direct collection or a filter size of 0.2 μm to capture bacteria, b) maximum flow rates for DNA yield, c) the ability ability to cope with the Arctic environment, d) a convenient power source (battery or generator) to enable long sample runs and e) preferably many users to provide data for comparison elsewhere. Pictured is one such example, the SAS (Surface Air System) Air Sampler as deployed in the field. (Photo: David Pearce)

  -and non-culture-based analyses, the liquid matrix can be split for various analyses low-capture rates, loss of collection fluid to evaporation and violent bubbling, loss of viability, liquid incompatible with chemical analysis Impaction cell death from impaction is insignificant, efficient means of obtaining total counts of fungal spores, ease of use, portability, assessment of culturable populations of bacteria and fungi per volume of air restricted use in the analysis of other microbial types (bacteria and viruses), loss of viability due to impact stress, loss of recovery efficiency, low sample volumes due to low flow rates Sticky traps Low expense, easy to use and install, perfect for counting of animals and plants directly on the trap. Dedicated to invertebrates and plant particles, often destroy invertebrate specimens; cannot be used for quantifying bacteria and fungi Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 73 / Table A2: Data availabilityand commentary to map in Figure A1.

Figure

  Figure A1: Distribution map, showing measurement sites relevant to the topic of atmospheric impurity monitoring and harmonisation

Table A1 ;

 A1 (oxides of carbon, sulphur and nitrogen, also H 2 and NH 3 ), through various forms of mercury in atmospheric air, to metals and metalloids in precipitation. Carbon dioxide concentrations are monitored there by Stockholm University; in parallel, weekly flask samples have been analysed for trace gas concentrations by NOAA/CMDL. The monitoring programme at Zeppelin spans also organic compounds: greenhouse gases (CH 4 , fluorinated gases), POPs and selected CEACs(AMAP 2011(AMAP , 2016;;[START_REF] Carlsson | AMAP 2016. Influence of Climate Change on Transport, Levels, and Effects of Contaminants in Northern Areas -Part 2[END_REF] AMAP 2017;[START_REF] Platt | Atmospheric composition in the European Arctic and 30 years of the Zeppelin Observatory, Ny-Ålesund[END_REF] Xie et al. 2022b), saccharides, VOCs and more (ebas-data.nilu.no/; see also section 6. Data availability). Furthermore, selected POPs and CEACs have been detected in air samples from Ny-Ålesund (as well as Longyearbyen, Barentsburg and Hornsund) via diverse national research projects (TableA1& section 6. Data availability). The concentrations of most POPs listed for control under the Stockholm Convention, e.g. PBDEs, PCBs and OCPs, showed clearly seasonal variation and declining trends over the year from 1990s to 2021(AMAP, 2016;[START_REF] Wong | Time trends of persistent organic pollutants (POPs) and Chemicals of Emerging Arctic Concern (CEAC) in Arctic air from 25 years of monitoring[END_REF]. Given the advances of sampling and analytical techniques, more and more novel CEACs have been identified and quantitatively detected in Arctic air (see Appendix[START_REF] Xie | Neutral Poly-/perfluoroalkyl Substances in Air and Snow from the Arctic[END_REF][START_REF] Wong | Time trends of persistent organic pollutants (POPs) and Chemicals of Emerging Arctic Concern (CEAC) in Arctic air from 25 years of monitoring[END_REF]. Unfortunately, the time trends of CEACs are not as clear

Their main facility is located on top of Mt. Zeppelin (joined since by other institutions), a unique site with much smaller influence of the local contamination factors than any other land-based station in Svalbard due to its elevation. NILU is collecting data on a wide range of variables there, from inorganic ions and gaseous Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 9 compounds as those for classic POPs, and the relatively high concentrations of CEACs in Arctic summer imply the impact of local sources or reemission from cryosphere (AMAP 2017; Xie et al. 2022a).

  aerosols (e.g., SOx, NOx), complex organic pollutants (e.g. POPs) and heavy metals (e.g., As, Cd, Pb). Quantifying the concentrations of those impurities in the seasonal snowpack allows to understand the accumulation and depletion mechanisms, and in consequence to assess the total load of contaminants potentially released by spring melt into the local food chain. Furthermore, air-snow exchange may significantly interfere with atmospheric concentrations of PFASs at Ny-Ålesund,

Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 10 secondary

  Since 2004, AOD instruments have been deployed periodically on various ships on waters around

Svalbard Island: RV Oceania

(2007( , 2009( -2020( , e.g. Leck et al. 2001;;[START_REF] Tjernström | The Arctic Summer Cloud Ocean Study (ASCOS): overview and experimental design[END_REF][START_REF] Heintzenberg | Potential source regions and processes of aerosol in the summer Arctic[END_REF]

, the Swedish ice-breaker

Oden (2008; ASCOS campaign -Chang et al. 2011;[START_REF] Sierau | Single-particle characterization of the high-Arctic summertime aerosol[END_REF]), RV Polarstern (2012[START_REF] Coulson | The alien terrestrial invertebrate fauna of the High Arctic archipelago of Svalbard: potential implications for the native flora and fauna[END_REF], 2017, 2020)

, RV Jan Mayen (

2009

); RV Akademik Mstislav Keldysh (2016; Terpugova et al. 2018) and RV Alliance (2021). The IOPAN RV Oceania participates in the Maritime Aerosol Network, the component of AERONET network, and provides ship-borne AOD measurement since 2007 in the Norwegian and Greenland Seas. Since 1987, IOPAN has been conducting a regular, annual AREX Arctic Expedition (Węsławski and Sagan 2020), performing meteorological surveys, measuring aerosol fluxes, physical and optical properties of aerosols from the start. Those cruises were conducted year by year with almost the same research plan, with continuity and repeatability both in time and space, covering about 90 days in the Arctic each summer (Ferrero et al. 2019; Pakszys et al. 2020). The RV Oceania's annual summer cruise is one of the longest monitoring programmes conducted in the Svalbard seas. Recently, in collaboration with the UNIMIB, also PAHs, n-alkanes, organic matter and trace elements have been added, irregularly.

The German research icebreaker RV Polarstern (of AWI) has a longer history with the Arctic than RV

  observations in Svalbard have shown that air-water/snow gas exchange alters the atmospheric concentrations of chemicals[START_REF] Yu | Polycyclic Aromatic Hydrocarbons Not Declining in Arctic Air Despite Global Emission Reduction[END_REF][START_REF] Araujo | Mercury isotope evidence for Arctic summertime re-emission of mercury from the cryosphere[END_REF][START_REF] Dastoor | Arctic atmospheric mercury: Sources and changes[END_REF]).

. Both ship-based and Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 16 stationary

  harmonisation of several measurement types in one monitoring protocol. In harmonisation attempts, key variables to consider are sampling consumables type (e.g. filter material or pore size), exposure time (or sampled air volume), and the analytical steps leading to final results.

The first group of chemicals with harmonised sampling regimes in the Svalbard monitoring is gaseous constituents measured on-line, such as the greenhouse gases (CH 4 , CO 2 , HFCs, SF 6 ), O 3 and several ozone-depleting chemicals (CFCs, HCFCs, halones, and other halogenated organic gases). The online measurements offer quick access to analytical results and high sampling frequencies, e.g. NILU monitors 23 gases at Zeppelin at least once per 4 hours (every 5 minutes for O 3 ). Most of these measurements are provided by automated GC systems with different detectors: FID for methane, MgO-UV for carbon monoxide, and MS for halogenated compounds

[START_REF] Myhre | Greenhouse gas monitoring at the Zeppelin station, Norway Mysłek-Laurikainen B[END_REF]

. CH 4 concentrations may also be measured with CRDS (ebas-data.nilu.no/). For longer-term averages,

  is based on two other techniques. The first is the thermal-optical methods, which measure EC and OC at the same time[START_REF] Caiazzo | Carbonaceous Aerosol in Polar Areas: First Results and Improvements of the Sampling Strategies[END_REF]. Active research networks have adopted different protocols to quantify EC (see WMO/GAW (2016) for details). EC measurements may differ by up to a factor of two due to differences in protocols, instruments, laser signals, and corrections for the chemical character of OC[START_REF] Karanasiou | Thermal-optical analysis for the measurement of elemental carbon (EC) and organic carbon (OC) in ambient air a literature review[END_REF]. Filter-based optical methods are another approach taken for long-term BC monitoring, providing outputs as eBC. Instrumentation available in Svalbard include the PSAP, aethalometer or MAAP[START_REF] Petzold | Multi-angle absorption photometry-a new method for the measurement of aerosol light absorption and atmospheric black carbon[END_REF]. Uncertainties in the filterbased absorption techniques are caused by non-BC aerosol compounds, which can either absorb or scatter the light when deposited on the filter, and by light scattering of the filter itself. Correction schemes have been developed for the Arctic to account for the effects mentioned above in the aethalometer absorption conversion[START_REF] Backman | On Aethalometer measurement uncertainties and an instrument correction factor for the Arctic[END_REF].Atmospheric POPs monitoring at Zeppelin is a key component of AMAP (e.g., AMAP 2016), and its collection and analysis method are therefore well established. In order to generate high quality data and comparable results, a standard operation protocol for air sampling and analysis has been harmonised through the analytical laboratories working within AMAP for classic POPs including PCBs, PBDEs, OCPs and PFASs. Standard operating procedures have been created on both active and passive air sampling for POPs monitoring. Newer studies of POPs aspire to match the standard techniques closely, e.g. at Barentsburg, PAHs and PCBs were determined in particulate matter

	collected on GFF (14 m	3 of air collected in 24 hours)

). Long-term monitoring of BC in the Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 18 atmosphere

  NILU Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA

	(impurity type + method in brief) POPs (mainly organochlorine pesticides and PCBs) by high-volume sampler black carbon by aethelometer black carbon by aethelometer Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in Parameter (Air/Aerosol = A; Snow/Rain = P) + temporal resolution of measurement (if known) Period Location (BAR = Barentsb urg; GVB = Gruveba det; HRN = Hornsun d; LYB = Longyear byen; NyA = Ny-Ålesund; ZEP = Mt. Zeppelin) Metadata access (URL) 1 A 1980-1983 NyA article: (Oehme & Ottar, 1984) 2 A; every 5 or 10 mins (two devices) 2011 NyA, Chinese Yellow River Station, and three other locations article doi: 10.3402/polar. v33.21821 3 A, every 10 mins 2005-2008 NyA, Chinese Yellow River Station article doi: 10.1175/JAS-D-15-0009.1 the Svalbard Atmosphere HERMOSA Page 23 Dataset provider NILU J. Zhan & Y. Gao (Rutgers University) L. Chen (State Oceanic Administration, Xiamen, China) et al. 4 trace gases (O 4 , BrO, OClO, NO 2 ) by MAX-DOAS A, continuous (every 2000 ms) 2017 NyA, Chinese Yellow River Station D. Chen 25351.filter_3 O01L_IC.lev2.n https://doi.org/ R. Traversi 1e7ff6361ac5 KOPRI.KR03L http://thredds.n seous_elemen _ADS_no42.N 4y.1h.NO01L_ .NO01L_picarr http://thredds NILU ek_no42_pm1 .US13L_glass_f Northumbria at https://doi.org/ W. Pusz & J. samler 766734200100 (Limnology EFI_2021_010 orin.lev2.nc article doi: 10.1016/j.scito tenv.2022.156 335 (Chinese Academy of Sciences, Hefei) et al. 5 mineral dust by copper TEM grids coated with carbon film A, 20 min -2 h 2012 NyA, Chinese Yellow River Station article dois: 10.5194/acp-19-10433-2019; 10.5194/acp-15-11341-2015 J. W. Chi (Shandong University, Jinan) et al.; H. Yu (Hangzhou Normal University) et al. 6 inorganic ions, conductivity (EC) and pH by bulk sampler P, daily in 1980-83, then weekly 1980-2021, EC only in 1984-85, gaps for particular parameters Ny-Alesund http://thredds .nilu.no/thred ds/fileServer/e bas/NO0057R. 00.202105121 10343.bulk_sa mpler.conduct ivity.precip.2y. 1w.NO01L_bs _w_0057.NO0 1L_cond_mete r.lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0057R. 00.201812101 33000.bulk_sa mpler.precipit ation_amount. precip.5y.1w. NO01L_precip _bulk_UK.NO0 1L_BW.lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0057R. 00.202105121 33009.bulk_sa mpler..precip. 4mo.1w.NO01 L_bs_w_0057.. lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e Page 26 pack...3y.1w.N O01L_f3p_w_ 1154.NO01L_I C.lev2.nc 8 inorganic ions by filter pack A, daily or weekly, depending on the period mid-2008-2018 Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 27 c 9 trace gases (e.g. CO, CH 4 , O 3 ) by FTIR spectroscopy NyA, AWIPEV station Data not directly available project website: https://www.iup. uni-bremen.de/ftir/c ms/ 10 pollen A, weekly 1986 NyA https://doi.org/ 10.3402/polar. v6i1.6842 S. Johansen & U. Hafsten 11 Atmospheric optical depth (AOD) / water vapour in the air column / inversion aerosol products A, depending on cloud cover Since 2017 (& March-April 2006) NyA https://aeronet. gsfc.nasa.gov/ new_web/data .html ; https://aeronet. gsfc.nasa.gov/ cgi-bin/data_displ ay_aod_v3?sit e=Ny_Alesund _AWI C. Ritter (AWI), AERONET 12 bacteria A 2018 NyA, GVB https://doi.org/ 10.1016/j.atmo senv.2021.118 458 M. Fetracco (CNR-ISP) 13 WSOC, phenolic compounds, trace elements and rare earths; in 6 dimensional classes of aerosol \ Andersen High volume cascade impactor the Svalbard Atmosphere HERMOSA Page 28 Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 29 Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 33 Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 35 Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 36 Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 37 Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 38 Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 42 the Svalbard Atmosphere HERMOSA Page 43 the Svalbard Atmosphere HERMOSA Page 44 the Svalbard Atmosphere HERMOSA Page 45 the Svalbard Atmosphere HERMOSA Page 46 the Svalbard Atmosphere HERMOSA Page 47 the Svalbard Atmosphere HERMOSA Page 48 the Svalbard Atmosphere HERMOSA Page 49 Page 51 the Svalbard Atmosphere HERMOSA Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in A, weekly Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in 14 EC/OC \ 2 TECORA low volume A, weekly Since 2010 NyA, GVB 10.3390/atmos 12030320 (UniFI) & G. Calzolai (INFN) 15 PM10 for elementary composition (PIXE) \ Sequential TECORA Skypost A, weekly Since 2010 NyA, GVB Upon request to R. Traversi R. Traversi (UniFI) 16 PM10 sampling for ionic compounds determination \ Sequential TECORA Skypost A, weekly Since 2010 NyA, GVB (Traversi et al. 2021) https://doi.org/ 10.3390/atmos 10070349 https://doi.org/ 10.1016/j.atmo senv.2021.118 890 https://doi.org/ 10.1007/s1221 0-016-0517-7 R. Traversi (UniFI) 17 Sampling of PM10 -determination of trace elements and lead isotopes \ TECORA High-Volume A, four days -now weekly Since 2010 NyA, GVB https://doi.org/ 10.3390/atmos 12091152 https://doi.org/ 10.3390/atmos 12030388 https://doi.org/ 10.1071/EN19 227 M. Malandrino (UniTO) & M. Grotti (UniGE) 18 Aerosol sampling in 4 dimensional classes for distribution of ions \ Dekati 4-stage impactor A, weekly From 2010 to 2018 NyA, GVB https://doi.org/ 10.1007/s1221 0-016-0529-3 R. Traversi (UniFI) 19 Spore and pollen sampling \ Cyclone A, weekly From 2018 NyA, GVB Upon request L. P. D'Acqui (CNR-IRET) 20 Ice Nucleating Particles (INP) \ TECORA PM10/PM1 A, campaign based From 2018 to 2020 NyA, GVB https://doi.org/ 10.5194/acp-21-14725-2021 M. Rinaldi et al. 21 Characterisation of WSOC in sub-micrometric aerosol with H-NMR & HR-TOF-AMS (all offline) \ TECORA Echo HVS PM1 A, weekly From 2018 -ongoing NyA, GVB https://sios-svalbard.org/m etsis/metadata /urn_uuid_it-cnr-dta-iadc-101 M. Rinaldi, M. Paglione (CNR-ISAC) 22 Microplastics, CEACs, PAHs \ TSP Tisch HVS A, weekly From 2021 -ongoing NyA, GVB upon request F. Corami, M. Vecchiato (CNR-ISP) 23 Optical properties of the aerosol \ Nephelometer, Radiance Res. A, weekly From 2010 -ongoing NyA, GVB upon request M. Mazzola (CNR-ISP) 24 Optical properties of the aerosol (including eBC) \ Radiance Res. (PSAP) A, daily to weekly From 2010 -ongoing NyA, GVB https://metadat a.iadc.cnr.it/ge onetwork/srv/e ng/catalog.sea rch#/metadata/ ee3fb49e-c3e2-4572-95b8-M. Mazzola, S. Gilardoni (CNR-ISP) 25 Optical properties of the aerosol and BC \ Aethalometer A, daily to weekly From 2021 -ongoing NyA, GVB upon request M. Mazzola, S. Gilardoni (CNR-ISP) 26 Aerosol size distribution, 523 nm-20 µm range \ Aerodynamic Particle Sizer A, daily to weekly From 2010 to 2020 NyA, GVB https://doi.org/ 10.3390/atmos 12020271 M. Mazzola (CNR-ISP); R. Traversi (UniFI) 27 Aerosol size distribution, 10-487 nm range \ SMPS A, daily to weekly From 2010 -ongoing NyA, GVB upon request M. Mazzola (CNR-ISP); R. Traversi (UniFI) 28 Passive sampler for dry deposition -SEM analysis (dimensional & chemical particle characterisation) \ Sigma-2 A, month From 2020 -ongoing NyA, GVB upon request P. Ielpo (CNR-ISAC); F. Scoto (CNR-ISAC) 29 Multiparametric optical characterisation of airborne dust with single particle extinction and scattering \ OPTAER A, days From 2022 -ongoing NyA, GVB upon request Marco Potenza (UniMib) 30 CO 2 , CH 4 , N 2 O, SF 6 and O 2 /N 2 ratio and stable isotope ratio of CO 2 A, weekly 03/2015-03/2019 NyA https://ads.nipr .ac.jp/dataset/ A20191217-006 D. Goto (NIPR) et al. 31 inorganic ions by filter pack cloud condensation nuclei (CCN) number concentration by a CCN counter A, hourly 2007-2015; 2018-2019 NyA, ZEP http://thredds.n ilu.no/thredds/f ileServer/ebas/ NO0042G.201 80101000000. 00.CCNC.clou d_condensatio n_nuclei_num ber_concentrat ion.aerosol.1y. 1h.KR03L_DM T_CCN-100-KOPRI _CCNC_2018. lev2.nc ; http://thredds.n ilu.no/thredds/f ileServer/ebas/ NO0042G.200 70101000000. 201910031141 00.CCNC.clou d_condensatio n_nuclei_num ber_concentrat ion.aerosol.9y. 1h.KR03L_DM T_CCN-100-KOPRI.KR03L _CCNC.lev2.n c ; http://thredds.n ilu.no/thredds/f ileServer/ebas/ NO0042G.201 90101000000. 202012160000 00.CCNC.clou d_condensatio n_nuclei_num ber_concentrat ion.aerosol.1y. 1h.KR03L_DM T_CCN-100-KOPRI.KR03L _CCNC_2019. lev2.nc 34 ozone by UV absorption A, hourly 1989-2022 NyA, ZEP http://thredds.n ilu.no/thredds/f ileServer/ebas/ NO0042G.198 90831230000. 202204070000 00.uv_abs.ozo ne.air.32y.1h. NO01L_uv_ab s_uk_0042.NO 01L_uv_abs.le v2.nc ; http://thredds.n ilu.no/thredds/f ileServer/ebas/ NO0042G.202 00108000000. 202208212105 10.uv_abs.ozo ne.air.3y.1h.N O01L_uv_abs _uk_0042_NR T.NO01L_uv_ abs.lev1.5.nc NILU ilu.no/thredds/f ileServer/ebas/ NO0042G.202 10101000000. 202203170000 00.Hg_mon.ga seous_elemen tal_mercury.air .1y.1h.NO01L _tekran_42.N O01L_afs.lev2 .nc ; http://thredds.n ilu.no/thredds/f ileServer/ebas/ NO0042G.200 30412144500. 201405010000 00.ann_denud er.reactive_ga seous_mercur y.air.25mo.1d. NO01L_rgm_4 2.NO01L_tekr an..nc ; http://thredds.n ilu.no/thredds/f ileServer/ebas/ NO0042G.200 10413080000. 200210300000 00.ann_denud er.reactive_ga seous_mercur y.air.13mo.1d. NO01L_rgm_4 2.NO01L_gard is_monitor..nc ; http://thredds.n ilu.no/thredds/f ileServer/ebas/ NO0042G.201 70101000000. 201801150000 00.Hg_mon.ga seous_elemen tal_mercury.air .1y.1h.NO01L _tekran_42.N O01L_afs..nc ; http://thredds.n ilu.no/thredds/f ileServer/ebas/ NO0042G.201 80101000000. 202205020832 09.Hg_mon.ga tal_mercury.air .3y.1h.NO01L _tekran_42.N O01L_afs.lev2 .nc ; http://thredds.n ilu.no/thredds/f ileServer/ebas/ NO0042G.202 10701013000. 202203240000 00.Hg_mon...6 mo.3h.NO01L _tekran_42_m odified.NO01L _afs.lev2.nc 36 halogenated greenhouse gases (CFCs; halons, HCFCs, HFCs, SF 6 and other halogenated compounds) by an online gas chromatograph (GC) A, daily; since 2010 every 2 hours 2001-2021 NyA, ZEP http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 200201010000 00.201207170 00000.online_ gc..air.9y.1d.N O01L_HP5973 _ADS_no42.N O01L_automat ic_desorption_ system..nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 201009010000 00.201308310 00000.online_ gc..air.28mo.1 d.NO01L_Agile nt_GC-MS_5973_ME DUSA_19_ZEP. NO01L_NILU_ MEDUSA..nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 200101010000 00.201101120 00000.online_ gc..air.1y.1d.N O01L_HP5973 NILU O01L_automat ic_desorption_ system..nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202205160 00000.online_ gc..air.11y.2h. NO01L_Medus a-19.NO01L_AG AGE.lev0.nc 37 H 2 by GC-HgO A, every 2 h 2006-2009 NyA, ZEP http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.200909070 00000.GC-HgO.hydrogen .air.3y.2h.NO0 1L_RGA3_no4 2.NO01L_RGA 3_MPI2009..n c 38 CO (carbon monoxide) by GC-HgO A, at least daily (every 2 h 2006-2008; hourly 2009-2012) 2001-2012 NyA, ZEP http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.200909070 00000.GC-HgO.carbon_ monoxide.air. 3y.2h.NO01L_ RGA3_no42.N O01L_RGA3..n c ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202205090 00000.GC-HgO.carbon_ monoxide.air. NILU RGA3_no42.N O01L_RGA3.le v2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.201307190 00000.GC-HgO.carbon_ monoxide.air. 11y.1d.NO01L _RGA3_no42. NO01L_RGA3.. nc 39 CO (carbon monoxide) by online CRDS A, hourly (daily in 2013) 2013-2022 NyA, ZEP http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.201408111 22844.online_ crds.carbon_m onoxide.air.19 mo.1d.NO01L_ picarro1_G240 1.NO01L_picar ro..nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202207180 83023.online_ crds.carbon_m onoxide.air.3y. 1h.NO01L_pic arro2_G2401_ ICOS.NO01L_p icarro.lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202202282 10212.online_ crds.carbon_m NILU o.lev1.5.nc 40 CO 2 and CH 4 , N 2 O by online CRDS A, hourly 2012-2022 NyA, ZEP https://sios-svalbard.org/m etsis/search?s earch_api_fullt ext_op=or&fullt ext=Zeppelin+ online-CRDS&start_d ate=&end_dat e=&is_parent= All&platform_a ncillary_cloud_ coverage=All& f%5B0%5D=d ataset_level% 3ALevel-1 3 NILU 41 PAHs by high-volume sampler A, weekly 2008 NyA, ZEP http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 200801070753 00.201812101 33000.high_vo l_sampler...1y. 1w.NO01L_fpp uf_42a..lev2.n c 42 POPs (mainly organochlorine pesticides and PCBs) by passive PUF samplers A, single sample 2006 NyA, ZEP http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 200607140000 00.201812101 33000.passive _puf..air.74d.3 mo.NO01L_pu f_42.NO01L_g c_ms.lev2.nc 43 POPs (mainly organochlorine pesticides and PCBs) by high-volume sampler A, weekly samples, representing 48-72 h pesticides regularly since 1994, PCBs since 1998; early measurements in 1984 NyA, ZEP article doi: 10.1016/j.envp ol.2016.01.079 ; 1984 data in article: http://www.jsto r.org/stable/43 13848; NILU 44 PFAS by high-volume sampler A, weekly samples, representing 48 h 2006-2014 NyA, ZEP article doi: 10.1016/j.atmo senv.2017.10. 028 P. Bohlin-Nizzetto (NILU) 45 OC/EC (organic carbon/elemental carbon) by high-volume sampler (in PM10) A, weekly 2017-2021 NyA, ZEP .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202204061 24026.high_vo l_sampler..pm 10.3y.1w.NO0 1L_hvs_week_ no42_pm10.N O01L_NILU_su nset_002.lev2. nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202204061 24026.high_vo l_sampler..pm 10.23mo.1w.N O01L_hvs_we ek_no42_pm1 0..lev2.nc 46 Saccharides by high-volume sampler A, weekly 2017-2021 NyA, ZEP http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202204061 24026.high_vo l_sampler.cell ulose.pm10.4y .1w.NO01L_hv s_week_no42 _pm10.AT05L_ spectrophoto metric_uv_34 0nm.lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202203170 00000.high_vo l_sampler..pm 10.12mo.1w.N O01L_hvs_we NILU 0.NO01L_UHP LC_50249.lev2 .nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202204061 24026.high_vo l_sampler..pm 10.2y.1w.NO0 1L_hvs_week_ no42_pm10.N O01L_UHPLC_ 50249.lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202204061 24026.high_vo l_sampler..pm 10.23mo.1w.N O01L_hvs_we ek_no42_pm1 0..lev2.nc 47 VOCs (volatile organic compounds) by adsorbent tube A, daily 1994-1998 NyA, ZEP http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.201812101 33000.ads_tub e..air.5y.1d.N O01L_DNPH_s ilica_tube_wat ers37500_no4 2.NO01L_HPLC _UV.lev2.nc 48 alkanes by glass flask A, weekly 2003-2016 NyA, ZEP http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202108312 00407.glass_fl ask..air.14y.1w Newcastle) et al. A, daily 2019 Area of 10.1007/s1066 Urbaniak 25 Institute, ; lask_NO0042G .US13L_GC_FI D_v1.lev2.nc 49 organic gaseous compounds by steel canister A, daily 1989-1999 (various periods for various gases) NyA, ZEP NOT HARVESTED INTO SIOS DATABASE -link unknown NILU 50 black carbon, number and mass concentrations by SP2 P, daily 09/2012-03/2018 NyA https://ads.nipr .ac.jp/dataset/ A20191018-008 K. Goto-Azuma (NIPR) et al. 51 black carbon, mass concentration, by SP2 A, hourly 03.2017 NyA https://ads.nipr .ac.jp/dataset/ A20191217-011 S. Ohata (Univ. of Nagoya) et al. 52 POPs and CEACs by high-volume sampler A, weekly 2011 NyA, AWIPEV Station (HEREO N) article doi: 10.1038/srep0 8912; more data in the process of obtaining dois at https://pangae a.de HEREON (Z. Xie) 53 black carbon, mass concentration, by COSMOS A, hourly (at least the first link, which is a dataset starting in 10/2012) 04/2009-10/2019 NyA https://ads.nipr .ac.jp/data/met a/A20180402-008/record; http://doi.org/1 0.17592/001.2 020112001 M. Koike (Univ. of Tokyo) et al. 54 microfauna A, weekly 2000, 2001 NyA https://doi.org/ 10.1007/s0030 0-003-0516-x S. Coulson (UNIS) et al. 55 pollen, bryophyte spores A, daily 1950 Sarsbukta https://doi.org/ 10.1139/b55-03 N. Polunin 56 dust deposition A+P, yearly 2012-2022 Petuniabu kta https://doi.org/ 10.1016/j.cate na.2021.10597 4 Krzysztof G. Rymer (UAM Poznan) 57 dust deposition P, campaign based 2019 Petuniabu kta https://doi.org/ 10.5281/zenod o.6790470 J. Kavan (Uni. Wroclaw & Masaryk University, Czech Rep.) 58 bacteria A, once 2015 Billefjorde n doi:10.3390/bi ology602002 L. Cuthbertson (University of Northumbria at Newcastle) et al. 59 bacteria A, once 2015 Gipsdalen doi:10.3390/bi ology602002 L. Cuthbertson (University of Northumbria at Newcastle) et al. 60 bacteria A, once 2015 Sassenfjo rden doi:10.3390/bi ology602002 L. Cuthbertson (University of 61 bacteria A, once 2015 Deltanese t doi:10.3390/bi ology602002 L. Cuthbertson (University of Northumbria at 74 fungi LYB 1-021-09090-2 A, once 2015 Mine doi:10.3390/bi L. Cuthbertson (University of Northumbria at Siberian Branch, Russian Academy of Sciences) et al. 10.25171/Inst http://thredds NILU Geoph_PAS_I .nilu.no/thred GData_AVSE EFI_2021_011 ds/fileServer/e Newcastle) et al. 62 bacteria A, once 2015 Adventfjor den doi:10.3390/bi ology602002 75 bacteria (Gruve) 7 ology602002 Newcastle) et al. data available AARI paleo ; bas/NO0037R. L. Cuthbertson (University of Northumbria at Newcastle) et al. 63 bacteria A, once 2015 Isfjorden doi:10.3390/bi ology602002 L. Cuthbertson (University of Northumbria at Newcastle) et al. 64 fungi A, daily 2019 Area of LYB https://doi.org/ 10.1007/s1066 1-021-09090-2 W. Pusz & J. Urbaniak 65 Atmospheric optical depth (AOD) / water vapour in the air column / inversion aerosol products A, depending on cloud cover 2003-2004; 2018 LYB https://aeronet. gsfc.nasa.gov/ new_web/data .html ; https://aeronet. gsfc.nasa.gov/ cgi-bin/data_displ ay_aod_v3?sit e=Longyearby en B. Holben (NASA), AERONET 66 PAHs, oxy-and nitro-PAHs, by high-volume sampler A, on days with predicted NW wind direction 28 August -28 September 2018 LYB (UNIS roof) article doi: 10.5194/acp-20-9997-2020 T. Drotikova (UNIS) et al. 67 PAHs, oxy-and nitro-PAHs, by high-volume sampler A, 31 samples in total, 24 h each (~weekly) Nov 2017 -Jun 2018 LYB (UNIS roof) article doi: 10.5194/acp-21-14351-2021 T. Drotikova (UNIS) et al. 68 BTEX (aromatic VOCs) by GC-FID A, every 15 mins 2007 LYB article doi: 10.1021/es900 449x S. Reimann (Empa, Switzerland) et al. 69 bacteria A, four 2015 LYB doi:10.3390/bi ology602002 L. Cuthbertson (University of Northumbria at Newcastle) et al. 70 bacteria A, once 2015 Bjørndale n doi:10.3390/bi ology602002 L. Cuthbertson (University of Northumbria at Newcastle) et al. 71 fungi A, daily 2019 Area of LYB https://doi.org/ 10.1007/s1066 1-021-09090-2 W. Pusz & J. Urbaniak 72 PAHs, oxy-and nitro-PAHs, by high-volume sampler A, on days with predicted NW wind direction 28 August -28 September 2018 LYB (Aurora station Adventdal en) article doi: 10.5194/acp-20-9997-2020 T. Drotikova (UNIS) et al. 73 fungi A, daily 2019 Area of LYB https://doi.org/ 10.1007/s1066 1-021-09090-2 W. Pusz & J. Urbaniak 76 fungi A, daily 2019 Area of LYB https://doi.org/ 10.1007/s1066 1-021-09090-2 W. Pusz & J. Urbaniak 77 pollen by sticky trap A, weekly 2022 BAR CALM site data available by request; RiS projects 11316 and 10855 AARI paleo reconstruction group 78 PAHs, PCBs and trace metals, by multichannel sampler PU-4EP A, twice a year since 2002 BAR data avilable by request at RPA "Typhoon", North-West branch RPA "Typhoon" 79 trace gases (NO x , NO 2 , NO, NH 3 , SO 2 , H 2 S, CO 2 , CO, O 3 ) + PM10 + mercury by Lumex AAS A, continuous, 10 min (Hg) 2017-2021 BAR mountain data stored at AARI, currently not online; RiS ID 10863 AARI 80 pollen by sticky trap A, weekly 2017-2019; 2022 BAR data available by request; RiS projects 11316 and 10855 AARI paleo reconstruction group 81 pollen by sticky trap A, weekly 2017-2019; 2022 BAR data available by request; RiS projects 11316 and 10855 AARI paleo reconstruction group 82 trace gases (NO x , NO 2 , NO, NH 3 , SO 2 , H 2 S, CO 2 , CO, O 3 ) + PM10 + mercury by Lumex AAS A, continuous, 10 min (Hg) 2017-2022 BAR town data stored at AARI, currently not online; RiS ID 10863 AARI 83 AOD, water vapor content, aerosol concentration and size distribution, BC concentration by sun photometer, photoelectric particle counter, aetholometer A, continuous 2011-2022 BAR article dois: 10.1117/12.22 48456; 10.1134/S102 485601901014 7 D. G. Chernov (V.E. Zuev Institute of Atmospheric Optics SB RAS, Tomsk) et al.; S. Sakerin et al. 84 inorganic ions (ion chromatrography) and dissolved trace metals (ICP-MS) by low-volume sampler A, weekly 2011-2022 BAR article dois: 10.15356/2076 -6734-2013-2-129-136; 10.31857/S20 766734200100 25 L. P. Golobokova (Limnology Institute, Siberian Branch, Russian Academy of Sciences) et al. 85 PAHs by GC/MS TripleQuad, low volume A, campaign based 2017 BAR article doi: 10.31857/S20 L. P. Golobokova 86 pollen by sticky trap A, weekly by request; reconstruction https://doi.org/ 2017-2019; 2022 BAR RiS projects 11316 and 10855 group 87 snow chemical composition: major ions, HCO 3 -, pH, conductivity P, every fresh snow episode > 5 mm 2005 -2019 Hansbree n glacier (HRN) data available: https://monitori ng-hornsund.igf.e du.pl/index.ph p/login IG PAS (A. 10.25171/Inst Geoph_PAS_I P, monthly 00.201812101 1980-1987 33000.bulk_sa GData_AVSE mpler..precip. EFI_2021_012 4 8y.1mo.NO01L Nawrot) 88 snow chemical composition: major ions, HCO 3 -, pH, conductivity P, every fresh snow episode > 5 mm Since 2020 -ongoing Ariebreen glacier (HRN) data available: https://monitori ng-hornsund.igf.e IG PAS (A. 93 radionuclides: Concentration of: 7 Be, 210 Pb, 40 K, 137 Cs, 134 Cs [μBq/m 3 ] PM (dust) [μq/m https://doi.org/ 10.1016/j.jenvr A. Burakowska, _Nbs_37.NO0 metal concentrations (Cd, Pb, Zn) by bulk 1L_icp_ms.lev M. Kubicki (IG 97 sampler Bjørnøya 2.nc PAS) http://thredds ad.2021.10673 3 ] A, weekly Since 2002 HRN 9 .nilu.no/thred Nawrot) https://aeronet. gsfc.nasa.gov/ new_web/data P. Sobolewski ds/fileServer/e (IG PAS), bas/NO0037R. AERONET du.pl/index.ph p/login 89 metals and metalloids in precipitation, by ICP-MS, and TOC by a Shimadzu TOC Analyser P, every event 2010-2012 HRN precipitati on gauge Summary data in supplementary to the article doi: 10.3402/polar. v34.24207 K. Kozak 94 Atmospheric optical .html ; network 00.201812101 https://aeronet. gsfc.nasa.gov/ 33000.bulk_sa (Gdansk Tech) depth (AOD) / water cgi-mpler..precip. et al. 90 POPs (organochlorine pesticides and PCBs) in snow P, every event during 1 month; weekly surface snow at environmental chamber 2019 HRN area K. Koziol vapour in the air column / inversion aerosol products A, depending on cloud cover Since March 2005 HRN bin/data_displ 1y.1d.NO01L_ ay_aod_v3?sit bs_d_0037..le e=Hornsund article: Oehme v2.nc ; NILU http://thredds & Ottar, GEOPHYSICA .nilu.no/thred (Gdansk Tech) L RESEARCH ds/fileServer/e doi: A 1980-1983 LETTERS, bas/NO0037R. 10.34808/2cd8 POPs (mainly VOL. 11, NO. -pk41 91 precipitation chemistry: major ions, HCO 3 -, pH, conductivity; sum of the precipitation P, daily Since 2005 -ongoing HRN data available: https://monitori ng-hornsund.igf.e du.pl/index.ph p/login IG PAS (A. Nawrot) 92 aerosol concentration, aerosol size distribution (0.01-10 µm), aerosol vertical distribution A, 1 min (concentration) ; 10 min (size distribution) 2021 HRN https://doi.org/ 10.25171/Inst Geoph_PAS_I D. Kępski, M. Posyniak (IG PAS) 95 organochlorine pesticides and PCBs) by high-volume sampler Hopen 11, PAGES 1133-1136, 1984 A, daily 1978-1989 http://thredds .nilu.no/thred P, daily 00.201812101 1977-1985 33000.bulk_sa (various periods mpler..precip. within that 1y.1d.NO01L_ timespan) bs_37..lev2.nc ds/fileServer/e ; bas/NO0037R. http://thredds 198901010700 .nilu.no/thred 00.201812101 ds/fileServer/e 33000.filter_3 pack...7mo.1d. bas/NO0037R. GData_AVSE EFI_2021_008 ; https://doi.org/ 10.25171/Inst Geoph_PAS_I GData_AVSE EFI_2021_009 ; https://doi.org/ 10.25171/Inst Geoph_PAS_I 96 sulphate and sulphur dioxide concentrations by a filter pack Bjørnøya NO01L_f3p_2 00.201812101 d_0037.NO01L 33000.bulk_sa _IC.lev2.nc ; mpler..precip. http://thredds 8y.1mo.NO01L .nilu.no/thred _Nbs_37.NO0 ds/fileServer/e 1L_icp_ms.lev ion concentrations (NH 4 + , Ca 2+ , Cl -, Mg 2.nc ; 2+ , K + , Na + , NO 3 -, SO 4 http://thredds 2-) by .nilu.no/thred bulk sampler; GData_AVSE 98 conductivity and pH Bjørnøya ds/fileServer/e

NILU Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA NILU Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA

E. Barbaro (CNR-ISP, UNIVE)2 Dataset could be request to E. Barbaro (CNR-ISP, UNIVE) partial dataset are available on PANGAEA https://doi.org/10.1594/PANGAEA.928238

NILU

Search link provided here as an exception to save spaceit covers 134 datasets.

Entire dataset available on the project subpage https://dataportal.igf.edu.pl/group/avseefi; registration on the website is required to download the data; field data were collected inside a polygon defined by the coordinates in Fig.1; basic measurements in a fixed position are continued with the SPS30 micro sensor

Acknowledgements

This work was funded by the Research Council of Norway, project no. 322387, Svalbard Integrated Arctic Earth Observing System -Knowledge Centre (SIOS), operational phase 2022. The workshop organised within the scope of SSG project no. 311270 (HERMOSA) contributed initial ideas. The chapter was supported by a subsidy of the Ministry of Education and Science in Poland for the IG

Harmonising Environmental Research and Monitoring of Priority Pollutants and Impurities in the Svalbard Atmosphere HERMOSA Page 24 bas/NO0057R. 00.202105121 33009.bulk_sa mpler..precip. 2y.1w.NO01L_ bs_w_0057..le v2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0057R. 00.202105121 33009.bulk_sa mpler..precip. 1y.1w.NO01L_ bs_w_0057..le v2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0057R. 00.202105121 33009.bulk_sa mpler..precip. 2y.1w.NO01L_ bs_w_0057..le v2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0057R. 00.201812101 33000.bulk_sa mpler..precip. 1y.1d.NO01L_ bs_d_0057..le v2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0057R. 00.202105121 33009.bulk_sa mpler..precip. 3y.1w.NO01L_ bs_w_0057..le Page 25 v2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0057R. 00.201812101 33000.bulk_sa mpler..precip. 16mo.1d.NO0 1L_bs_d_0057 ..lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0057R. 00.201812101 33000.bulk_sa mpler..precip. 1y.1d.NO01L_ bs_d_0057..le v2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0057R. 00.202204051 23422.bulk_sa mpler..precip. 31y.1w.NO01L _bs_w_0057..l ev2.nc 7 inorganic ions by filter pack A, weekly 2019-2021 NyA, Tranform atorbua http://thredds .nilu.no/thred ds/fileServer/e bas/NO1154R. 00.202204051 25351.filter_3 pack...5w.1w. NO01L_f3p_w _1154.NO01L_ IC.lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO1154R. 00.202204051 NILU NyA, Nordpolh otellet http://thredds .nilu.no/thred ds/fileServer/e bas/NO1665R. 00.201805291 03658.filter_3 pack.magnesiu m.aerosol.6y.1 d.NO01L_f3p_ d_1665.NO01L _IC.lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO1665R. 00.201808170 00000.filter_3 pack..aerosol. 18mo.1d.NO0 1L_f3p_d_166 5.NO01L_IC.le v2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO1665R. 00.201810240 00000.filter_3 pack..aerosol. 17mo.1d.NO0 1L_f3p_d_166 5.NO01L_IC.le v2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO1665R. 00.201903281 42000.filter_3 pack..aerosol. 4y.1w.NO01L_ f3p_d_1665.N Since 2010 NyA, GVB https://doi.org/ 10.1594/PAN GAEA.928238 https://doi.org/ 10.1016/j.atmo senv.2021.118 458 https://doi.org/ 10.3390/atmos 12060694 https://doi.org/ 10.1016/j.scito tenv.2020.142 954 https://doi.org/ 10.1016/j.che mosphere.201 8.12.147 https://doi.org/ 10.1016/j.scito tenv.2019.136 089 https://doi.org/ 10.1007/s1221 0-016-0518-6 https://doi.org/ 10.1021/es400 125r A, daily 1989-2021, with breaks NyA, ZEP http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 199301010700 00.202104201 42507.filter_3 pack...8y.1d.N O01L_f3p_d_0 042.NO01L_IC. lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 200101010700 00.202104201 42507.filter_3 pack...10y.1d. NO01L_f3p_d_ 0042.NO01L_I C.lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. NILU Page 30 00.202104211 12338.filter_3 pack..aerosol. 18y.1d.NO01L _f3p_d_0042. NO01L_IC.lev2 .nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202104201 42507.filter_3 pack...1y.1d.N O01L_f3p_d_0 042.NO01L_IC. lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202104201 42507.filter_3 pack.sulphur_ dioxide.air.28y .1d.NO01L_f3 p_d_0042.NO 01L_IC.lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202204051 23416.filter_3 pack...4y.1d.N O01L_f3p_d_0 042.NO01L_IC. lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202104211 12338.filter_3 pack...6y.1d.N Page 31 O01L_f3p_d_0 042.NO01L_IC. lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202104201 42507.filter_3 pack.sulphate _total.aerosol. 3y.1d.NO01L_f 3p_d_0042.N O01L_IC.lev2.n c ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202104211 12338.filter_3 pack.sulphate _corrected.aer osol.1y.1d.NO 01L_f3p_d_00 42.NO01L_IC.l ev2.nc 32 "heavy metals" (As, Cd, Co, Cr, Cu, Fe, Pb, Mn, Ni, Ti, V, Zn) by high volume sampler A, weekly 1994-2021, with breaks NyA, ZEP http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.201812101 33000.high_vo l_sampler..aer osol.1y.1w.NO 01L_fphv42.N O01L_icp_ms.l ev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.201812101 33000.high_vo l_sampler..aer osol.1y.1w.NO 01L_fphv42.N Page 32 O01L_icp_ms.l ev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.201812101 33000.high_vo l_sampler..aer osol.23y.1w.N O01L_fphv42. NO01L_icp_m s.lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202104151 05909.high_vo l_sampler..aer osol.2y.1w.NO 01L_NILU_hvs _2d_0042.NO 01L_icp_ms.le v2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202204201 00159.high_vo l_sampler..aer osol.3y.1w.NO 01L_NILU_hvs _2d_0042.NO 01L_icp_ms.le v2.nc Page 40 22545.online_ crds..air.2y.1h. NO01L_picarr o1_G2401..lev 2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202207180 83023.online_ crds..air.1y.1h. NO01L_picarr o2_G2401_IC OS.NO01L_pic arro.lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202207180 83023.online_ crds..air.3y.1h. NO01L_picarr o2_G2401_IC OS.NO01L_pic arro.lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202202282 13456.online_ crds...3y.1h.N O01L_picarro_ G5310_NRT.N O01L_picarro.l ev1.5.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202208220 10220.online_ crds...59d.1h. NO01L_picarr o4_G2401_NR Page 41 T.NO01L_picar ro.lev1.5.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202208221 60216.online_ crds...8y.1h.N O01L_picarro4 _G2401_NRT. NO01L_picarr o.lev1.5_dup1. nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202208220 10220.online_ crds...8y.1h.N O01L_picarro4 _G2401_NRT. NO01L_picarr o.lev1.5_dup1. nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.202208221 60618.online_ crds...59d.1h. NO01L_picarr o4_G2401_NR T.NO01L_picar ro.lev1.5.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0042G. 00.201809110 81359.online_ crds..air.59w.1 h.NO01L_picar ro_G2401_te mp_2017_NRT Page 50 bas/NO0037R. 00.201812101 33000.filter_2 pack...3y.1d.N O01L_f2p_37. NO01L_IC.lev2 .nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0037R. 00.201812101 33000.filter_3 pack...1y.1d.N O01L_f3p37.N O01L_IC.lev2.n c ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0037R. 00.201812101 33000.filter_2 pack...5y.1d.N O01L_f2p_37.. lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0037R. 00.201812101 33000.filter_2 pack...2y.1d.N O01L_f2p_37. NO01L_thorin. lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0037R. 00.201812101 33000.filter_2 pack.sulphur_ dioxide.air.1y. 1d.NO01L_f2p _37.NO01L_th Page 52 bas/NO0037R. 00.201812101 33000.bulk_sa mpler..precip. 1y.1d.NO01L_ bs_37..lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0037R. 00.201812101 33000.bulk_sa mpler..precip. 2y.1d.NO01L_ bs_d_0037..le v2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0037R. 00.201812101 33000.bulk_sa mpler..precip. 1y.1d.NO01L_ bs_d_0037..le v2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0037R. 00.201812101 33000.bulk_sa mpler.potassiu m.precip.1y.1d .NO01L_bs_d_ 0037.NO01L_a as_2.lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0037R. 00.201812101 33000.bulk_sa mpler..precip. 2y.1d.NO01L_ Page 53 bs_37..lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0037R. 00.201812101 33000.bulk_sa mpler..precip. 1y.1d.NO01L_ bs_d_0037..le v2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0037R. 00.201812101 33000.bulk_sa mpler..precip. 1y.1d.NO01L_ bs_37..lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0037R. 00.201812101 33000.bulk_sa mpler..precip. 2y.1d.NO01L_ bs_37..lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0037R. 00.201812101 33000.bulk_sa mpler..precip. 1y.1d.NO01L_ bs_37..lev2.nc ; http://thredds .nilu.no/thred ds/fileServer/e bas/NO0037R. 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 [START_REF] Paglia | A higher level of civilisation? The transformation of Ny-Ålesund from Arctic coalmining settlement in Svalbard to global environmental knowledge center at 79° North[END_REF]