Baptiste Poirier
email: baptiste.poirier@cerema.fr

Gaëlle Guyot

Hugo Geoffroy

Monika Woloszyn

Michel Ondarts

Evelyne Gonze

Pollutants emission scenarios for residential ventilation performance assessment. A review

Keywords: Ventilation, indoor air quality, performance, residential buildings, scenarios, review

Performance-based approaches for energy consumption in new buildings are increasingly used in codes and standards. Similarly, there is ongoing research on performance-based approaches for ventilation systems. The aim is to assess indoor air quality (IAQ) performance in low-energy houses at the design stage. In this context, the whole-building IAQ performance modelling process raises a very important question: What are the emission scenarios and occupancy schedules to be used as entry data to calculate the selected performance indicators? We focus on this issue through a literature review: firstly oriented toward the occupancy considerations so as to define the emission rates for CO 2 , moisture, formaldehyde and PM 2.5 to be use as input for ventilation performance assessment.

Based on this review, we propose daily schedules for the occupants and their associated moisture and CO 2 emissions. We completed them with emission rate values for the main pollutant sources from indoor activities regarding moisture emissions from laundry, showering and cooking; PM 2.5 emissions from cooking and formaldehyde from building materials and furniture. Finally, from these values we built three emission rates classified for PM 2.5 and formaldehyde: high, medium and low.

Introduction

Net zero-energy residential buildings are in increasing demand in Europe because of the energy performance building directive [1]. Ventilation strategies have a large impact on the heat balance and the associated air conditioning energy need. Improving ventilation strategies also has great potential to reduce the contribution of residential buildings to total energy consumption.

Ventilation systems and strategies play another important role in buildings' indoor air quality (IAQ), significantly affecting public health [START_REF] Klepeis | The National Human Activity Pattern Survey (NHAPS): a resource for assessing exposure to environmental pollutants[END_REF][START_REF]Communiqué de presse -Indoor air pollution: new EU research reveals higher risks than previously thought[END_REF][START_REF] Brasche | Daily time spent indoors in German homes--baseline data for the assessment of indoor exposure of German occupants[END_REF][START_REF] Zeghnoun | Description du budget espace-temps et estimation de l'exposition de la population française dans son logement[END_REF][START_REF] Jantunen | European Commission, Directorate General for Health & Consumers, Promoting actions for healthy indoor air (IAIAQ)[END_REF]. People spend 60-90% of their life in indoor environments (homes, offices, schools, etc.). The current damage to public health estimated by Logue et al. [START_REF] Logue | Hazard assessment of chemical air contaminants measured in residences[END_REF] in disability-adjusted life years (μDALY) per person per year from all sources attributable to IAQ, excluding second-hand smoke (SHS) and radon, ranged between the health effects of road traffic accidents (4,000 μDALY.pers -1 .year -1 ) and heart disease from all causes (11,000 μDALY.(pers -1 .year -1 ).

Health gains in Europe (EU-26) attributed to effective implementation of the energy performance building directive, which includes indoor air quality issues, have been estimated at more than 300,000 DALYs per year.

In this context, in new certifications and future building regulations, building performance should be extended to indoor environment quality, beyond simply energy performance. In the energy performance field, successive regulations encouraged a performance-based approach, based on an energy consumption requirement for heating and/or cooling at the design stage [START_REF] Spekkink | Key note presentation on Performance-Based Building (PeBBu)[END_REF]. In the building ventilation field, regulations throughout the world are mainly still based on prescriptive approaches, with airflow or air change rate requirements [START_REF] Dimitroulopoulou | Ventilation in European dwellings: A review[END_REF]. There is ongoing research on performance-based approaches for residential building ventilation; aiming to replace prescriptive approaches. Indeed, the latter methods, with prescribed ventilation rates only, are an imperfect way to achieve a given IAQ. On the opposite, a performance-based approach, using for example IAQ performance indicators instead of ventilation rates, should be more appropriate.

Given the lack of relevant performance evaluation method for ventilation systems, we previously developed a performance-based approach for assessing ventilation performance at the building scale, at the end of the design stage, much like the regulatory energy performance calculation. This would ensure that ventilation is designed to avoid risks for occupants' health. We should also keep in mind, that Indoor Air Quality relies on two main principles: reduction of indoor pollution sources and efficient ventilation. Indeed, the ventilation system can not ensure the all pollutant dilution without a significant impact on the building energy performances. The need to reduce sources of indoor pollution is also a key element in ensuring good IAQ, for example by avoiding smoking cigarettes indoors, burning candles etc… Sources reduction is out of the frame of the developed method, which is focussing exclusively on the ventilation performance assessment. The following scheme gives an overview of the whole building IAQ modelling process for this performance-based approach, the inputs and outputs needed, and identifies the scope of the present paper (Figure 1). Relevant pollutants and performance indicators have been investigated and are often based on at least moisture, CO 2 , formaldehyde and particle matter PM 2.5 [START_REF] Guyot | Performance based approaches in standards and regulations for smart ventilation in residential buildings: a summary review[END_REF][START_REF] Guyot | Modelling the impact of multizone airleakage on ventilation performance and indoor air quality in low-energy homes[END_REF]. Indeed, formaldehyde and PM 2.5 are considered as two pollutants of concern in residential indoor air and were identified among the five pollutants with the highest median DALY loss estimates [START_REF] He | Contribution from indoor sources to particle number and mass concentrations in residential houses[END_REF][START_REF] Logue | Hazard assessment of chemical air contaminants measured in residences[END_REF]. In detail, the indoor sources contributing to elevated indoor particle matter levels are mainly related to human activities that generate peak emissions [START_REF] Kirchner | État de la qualité de l'air dans les logements français[END_REF]. On the contrary, the sources of formaldehyde emissions are more uniformly distributed, both in space and time, and related to building construction materials, furniture and decorative materials [START_REF] Logue | A Method to Estimate the Chronic Health Impact of Air Pollutants in U.S. Residences[END_REF][START_REF] Logue | Hazard assessment of chemical air contaminants measured in residences[END_REF][START_REF] He | Contribution from indoor sources to particle number and mass concentrations in residential houses[END_REF][START_REF] Kirchner | État de la qualité de l'air dans les logements français[END_REF][START_REF] Koistinen | The INDEX project: executive summary of a European Union project on indoor air pollutants[END_REF][START_REF] Who | WHO Guidelines for Indoor Air Quality: Selected Pollutants[END_REF][START_REF] Borsboom | TN 68: Residential Ventilation and Health[END_REF]. This makes PM 2.5 and formaldehyde interesting for their complementarity. Moisture and CO 2 where selected as historical parameters widely used in the standards and in ventilation systems controls [START_REF] Guyot | Performance based approaches in standards and regulations for smart ventilation in residential buildings: a summary review[END_REF][START_REF] Guyot | Smart ventilation energy and indoor air quality performance in residential buildings: A review[END_REF]. Indoor humidity level should be controlled in order to avoid problems related to condensation, mould growth and material durability. CO 2 concentration is related to human presence and is recognised as a marker for other bioeffluents.

Several other pollutants could have been selected, but for the performance-based method to be applied in practice, it is important to promote a low number of pollutants in order to build calculable and useful IAQ indicators.

To calculate IAQ performance indicators as cumulative exposures, we also need the occupancy schedules and parameters emission rates at the design stage of a building. In this paper, we focus on this second barrier aspect through an extensive literature review on the occupancy schedule considerations in a building and CO 2 , humidity, PM 2.5 and formaldehyde emission rate scenarios.

Methodology

We reviewed the available literature (Standards, Research reports, Scopus, Elsevier, AIVC database) using the following terms :

-First: "ventilation performance", "smart ventilation performance", "ventilation assessment", "ventilation IAQ performance".

-Second: "occupancy patterns", "occupancy schedules", "occupancy IAQ" and "occupant IAQ".

-Last: "IAQ emission", "IAQ rate", "IAQ sources", "emission rate", "cooking emission rate", combined with "CO 2 "a", "moisture", "humidity", "formaldehyde", "fine particle matter", "PM 2.5 ", "pollutant", "occupant".

The first important point we have to consider in this review is the accuracy of the emission rates. These data are not directly measured but are calculated using mass balance equations, combining airflows or air change rate measurements and parameter concentration measurements. As a result, several sources of uncertainty exist: measurement uncertainties on airflows and air change rates, measurement uncertainties on parameter concentrations, and modelling uncertainties (mass balance includes assumptions on occupancy, room configuration, weather data, etc.). Measurement uncertainties include the precision and bias of the measurement device, the impact of the user, the impact of the weather data (for air change rates and airflows), and is well documented in the ISO guide [START_REF]ISO/IEC, ISO/IEC Guide 98-3:2008 -Uncertainty of measurement --Part 3: Guide to the expression of uncertainty in measurement (GUM:1995)[END_REF]. Air change rates [START_REF] Remion | Review of tracer gas-based methods for the characterization of natural ventilation performance: Comparative analysis of their accuracy[END_REF][START_REF] Haghighat | The influence of turbulent wind on air change rates-a modelling approach[END_REF][START_REF] Kvisgaard | The user's influence on air change, Air Change Rate Airtightness Build[END_REF][START_REF] Modera | The Effects of Wind on Residential Building Leakage Measurements, Air Change Rate Airtightness Build[END_REF], ventilation airflows [START_REF] Cóstola | Uncertainty in airflow rate calculations due to the use of surface-averaged pressure coefficients[END_REF][START_REF] Bailly | Reliability of Ventilation System Inspection for Dwellings: Comparisons of Measurements and Controls Protocols Tested during in-Situ Campaigns of the Promevent Project[END_REF] and pollutant concentration measurement accuracy, notably sensor accuracy [START_REF] Fahlen | IEA Annex 18. Demand Controlled Ventilation Systems: Sensor Tests[END_REF][START_REF] Fisk | Accuracy of CO2 sensors in commercial buildings: a pilot study[END_REF][START_REF] Barsan | Metal oxide-based gas sensor research: How to?[END_REF][START_REF] Chung | Formaldehyde Gas Sensors: A Review[END_REF][START_REF] Guyot | Residential Smart Ventilation: A Review[END_REF][START_REF]AIVC, Webinar -IAQ sensors for smart ventilation of buildings[END_REF], are a broad area of research for in-situ and laboratory measurements. We selected only research papers and literature with consistent data on emission rates, with sufficient description of calculation methodology and of measurement uncertainties.

In addition, at the design stage of a residential building, it is difficult to fully describe occupancy for the entire life span of a building: number and age of the occupants, activities, schedules, etc. It is also impossible to precisely describe all the parameter emission rates for the occupants, their activities, the building materials and furnishings. In a performance-based approach at the design stage of a building, the standards and regulations dealing with this issue must also be considered.

We therefore preferred using cyclic schedules (fixed schedules which are reiterated every week), differentiating metabolic emissions, building and occupants' activity emissions, as proposed for humidity and CO 2 in several standards and regulations [START_REF] Guyot | Performance based approaches in standards and regulations for smart ventilation in residential buildings: a summary review[END_REF][START_REF]British standard, Ventilation principles and designing for natural ventilation[END_REF][START_REF] Mansson | IEA ECBCS Annex 27 Evaluation and Demonstration of Domestic Ventilation Systems Simplified Tools Handbook[END_REF][START_REF] Cen | Ventilation des bâtiments -Conception et dimensionnement des systèmes de ventilation résidentiels[END_REF][START_REF]Prénom) CEN, EN 15665 -Ventilation for buildings Determining performance criteria for residential ventilation systems[END_REF][START_REF] Johansson | Risk Assessment Model Applied on Building Physics: Statistical Data Acquisition and Stochastic Modeling of Indoor Moisture Supply in Swedish Multi-family Dwellings[END_REF][START_REF] Ccfat | VMC Simple Flux hygroréglable -Règles de calculs pour l'instruction d'une demande d'avis techniques -GS14.5 -Equipements / Ventilation et systèmes par vecteur air[END_REF]. The approach aims to provide a relative comparison of the performance of several ventilation systems, configurations and airflow rates, building design choices related to ventilation, IAQ labelling products, and even several occupant IAQ awareness levels.

Then we selected references allowing us to build a scenario to be used as entry data to calculate the performance indicators, in order to assess the ventilation performance of a building at its design stage.

This paper describes a detailed daily life required to calculate IAQ performance indicators. CO 2 and moisture performance indicators use occupants' metabolism and activity (only for humidity) emissions, combined with occupancy schedules, as input data. To calculate the cumulative exposure indicators (for instance, for formaldehyde and PM 2.5 ), we also need detailed occupancy schedules for each occupant. In this literature review, the duration of occupation by room throughout the day and the type of occupant (adult/child) were sought because they could influence the emission rates. In this section, we reviewed 10 papers.

Then the rates and scenarios for moisture, CO 2 and HCHO, PM 2.5 emissions were studied. CO 2 and moisture emissions from human metabolism and activities are quite well documented. We reviewed 12 papers and then built and proposed a scenario based on this analysis.

In contrast, formaldehyde and PM 2.5 emission rates remain exploratory, especially in a design approach for ventilation performance assessment. These pollutant emission and concentration measurements and modelling are complex, because of the physics of phenomena involved (e.g. diffusion, resuspension for PM, combined effects for formaldehyde) and available measurement techniques. In addition, formaldehyde emissions are highly dependent on building and furnishing materials. Consequently, we attempted to build low-, medium-and high-polluting emission rate scenarios and chiefly focus on measured pollutant emission rates stemming from the building, the furnishings and the occupants' activities. However, multiple types of data are available and cannot be directly used together for scenario proposals, so they were categorised in the formaldehyde and PM 2.5 sub-sections in three measurement types:

-Chamber-tested loads: Pollutant emissions due to specific activities, products and building materials obtained using test chambers under standardised conditions as described for VOC in ISO 16000-9 [38]. We found more data on formaldehyde than PM 2.5 emission rates.

-Lab kitchen: PM 2.5 emissions due to specific activities measured in unoccupied homes or in experimental setups.

-In-situ loads: Emission rates measured at the dwelling scale in occupied or unoccupied buildings, resulting from the combination of pollutant concentration and air change rate measurements in dwellings. We found few data on formaldehyde and PM 2.5 emission rates.

For PM 2.5 emissions, of the first 29 references analysed on emission sources and particle exposure in indoor environments, we selected eight published articles to build and propose a scenario based on this analysis. For formaldehyde emissions, we reviewed 22 references to build a scenario.

At the end, based on 73 articles reviewed, we provide a summary of the occupancy and emission rate scenarios selected. For emission rates, we conducted a review of the international literature, then we selected the rates and built the scenarios for a European, or even French application.

Occupancy considerations

Residential occupancy schedules in the literature

Precisely described data fitting our purposes are rarely found in the literature. Energy performance calculation methods use global occupancy schedules at a whole building scale (indoor/outdoor), whereas a multizone approach requires assuming an occupancy scenario in each room of the house, at each time step, both for the emission rates and exposure aspects.

In energy performance calculations, [START_REF] Aerts | Discrete occupancy profiles from time-use data for user behaviour modelling in homes[END_REF] proposed seven discrete occupancy profiles based on a time survey on more than 3000 Belgian dwellings. They differentiated outside, inside awake and inside asleep contexts.

A French IAQ national campaign based on a representative sample of the population included 567 homes and 1612 occupants [START_REF] Zeghnoun | Description du budget espace-temps et estimation de l'exposition de la population française dans son logement[END_REF]. A total of 1375 occupants provided precise information on their schedules and occupation in the rooms (25% of the sample) so that a database of 1,386,000 tenminute time steps with precise information on occupant location was available and analysed in this study. The results show that people spend on average 67.3% of their time in their homes. This is consistent with results of other surveys in Europe (EXPOLIS, 56-66%) and in the United States (NHAPS: 68.7%). Other interesting results are available in this study:

-The differences between weekend days and week days are minimal: the 3 days with the highest occupancy duration are Sunday (16.6 h), Wednesday (16.5 h) and Saturday (16.3 h), followed by Thursday (16.1 h). Friday is the least occupied day (15.7 h).

-There is no statistical difference between working periods and holidays.

-Occupants are more likely to be at home between 12.00 pm and 2 pm and between 7 pm and 7 am.

-Time spent at home is divided, on average, into 9 h 16 min spent in bedrooms, 2 h 49 min spent in the living room, 2 h 40 min spent in the kitchen and 38 min spent in the bathroom.

To achieve the occupancy consideration in a building this schedule information needs to be completed by a description of the occupants. Human emissions stem from the metabolic functions such as respiration, transpiration and perspiration, depending on different factors such as age [START_REF] Mansson | IEA ECBCS Annex 27 Evaluation and Demonstration of Domestic Ventilation Systems Simplified Tools Handbook[END_REF] (contradicted by [START_REF] Bienfait | Guidelines for Ventilation Requirements in Buildings[END_REF]) and activity level. Because of the development and growth of the organs of a child, its basic metabolism can reach twice the adult rate. The basic metabolism is defined as the minimum energy expenditure of an organism to ensure daily functions at rest. It decreases between 6 years and 18 years: from 19% for boys to 27% for girls [START_REF] Knoebel | Energy metabolism[END_REF]. As a result, as explained by [START_REF] Déoux | Bâtir pour la santé des enfants[END_REF], even if their body surface area is lower, children's CO 2 and humidity emission rates are as high as those of adults and may even be higher. Measures taken in 20 occupied apartments showed that children's emissions were often under-estimated in the literature and were closer to adults' emissions [START_REF] Bernard | Performance de la ventilation et du bâti -Phase 3 -Performance énergétique et QAI des systèmes hygroréglables[END_REF],

with emissions measured at 13 L.h -1 . for a child and 16 L.h -1 for an adult. The ECA guidelines for ventilation requirements in buildings [START_REF] Bienfait | Guidelines for Ventilation Requirements in Buildings[END_REF] compiles data from three studies [START_REF] Rasmussen | The influence of human activity on ventilation requirements for the control of body odor[END_REF][START_REF] Pejtersen | Air Pollution Sources in Kindergartens[END_REF][START_REF] Thorstensen | Air pollution sources and indoor air quality in schools[END_REF], giving emission rates for adults and children (Table 1). Table 1. Pollutant load caused by occupants. Source: [START_REF] Bienfait | Guidelines for Ventilation Requirements in Buildings[END_REF]

Occupancy schedule proposal

For our purposes, we used the detailed data from the French IAQ national campaign [START_REF] Zeghnoun | Description du budget espace-temps et estimation de l'exposition de la population française dans son logement[END_REF]. The following daily occupancy duration (rounded for a 10-min time step simulation) was retained: These occupancy schedules should be carefully adapted depending on countries and their habits (meal times, school times, work times, etc.).

The number of occupants must be assumed, taking into account the size of the house, to avoid under-estimating the ventilation airflow rates. We would suggest setting the number of occupants based on the number of bedrooms, assuming two occupants in one bedroom and one in each of the others. At the design stage of a building, we could also assume that all occupants are adults, based on the data reported in Table 1.

In the next section, emissions due to occupants will occur where and when occupants are assumed to be present.

CO 2 emissions [L.h -1 .occupant -1 ] Water vapour [g.h -1 .

Moisture emission rates in the literature

In a building the main moisture sources are linked to the occupants' activities such as showering, cooking, dish washing and laundry drying. In addition, the building envelope helps to regulate indoor humidity by exchanging moisture flows with the indoor air. This phenomenon must be represented in the model in order to provide realistic results. We consider this phenomenon of moisture exchange as a buffer (part of the model) and not as an emission source.

In most of the references analysed, mainly including standards, related production is given for a precise activity with a duration per day, sometimes depending on the number of occupants [START_REF]British standard, Ventilation principles and designing for natural ventilation[END_REF][START_REF] Mansson | IEA ECBCS Annex 27 Evaluation and Demonstration of Domestic Ventilation Systems Simplified Tools Handbook[END_REF][START_REF] Cen | Ventilation des bâtiments -Conception et dimensionnement des systèmes de ventilation résidentiels[END_REF][START_REF]Prénom) CEN, EN 15665 -Ventilation for buildings Determining performance criteria for residential ventilation systems[END_REF][START_REF] Ccfat | VMC Simple Flux hygroréglable -Règles de calculs pour l'instruction d'une demande d'avis techniques -GS14.5 -Equipements / Ventilation et systèmes par vecteur air[END_REF] (Table 2). Note that two normative documents [START_REF] Cen | Ventilation des bâtiments -Conception et dimensionnement des systèmes de ventilation résidentiels[END_REF][START_REF]British standard, Ventilation principles and designing for natural ventilation[END_REF] proposing the schedule approach also alternatively suggest using an average constant moisture emission rate, depending on the overall moisture production and the number of occupants. Alternative approaches based on experimental measurements are also proposed [START_REF] Johansson | Risk Assessment Model Applied on Building Physics: Statistical Data Acquisition and Stochastic Modeling of Indoor Moisture Supply in Swedish Multi-family Dwellings[END_REF][START_REF] Pallin | Stochastic modeling of moisture supply in dwellings based on moisture production and moisture buffering capacity[END_REF] (Table 2). Laundry drying (b)

100 g.h -1 75 g.h -1 (150 g.h -1 ) 300 g.h -1 300 g 100g.h -1 50g.h -1 0.5 h 1 h 1 h 0.5 h / 6 min 2 h 20 h
CCFAT [START_REF] Ccfat | VMC Simple Flux hygroréglable -Règles de calculs pour l'instruction d'une demande d'avis techniques -GS14.5 -Equipements / Ventilation et systèmes par vecteur air[END_REF] EN 15665 [START_REF]Prénom) CEN, EN 15665 -Ventilation for buildings Determining performance criteria for residential ventilation systems[END_REF] Electric cooking device Gas cooking device Hand dish washing WC/shower/dish washing Laundry Inside drying (c) 2000 g.day -1 3000 g.day -1 400 g.day -1 200 g.day -1 .person -1 500 g.day -1 1500 g.day -1 .person The occupants' metabolism is also a source of humidity. The most frequent distinction between activity levels is when occupants are asleep or awake. For a household of three people, a study used a value of 2.4 kg.day -1 of water production in each room [START_REF] Woloszyn | The effect of combining a relative-humidity-sensitive ventilation system with the moisturebuffering capacity of materials on indoor climate and energy efficiency of buildings[END_REF]. Experimental studies also give useful information with confidence intervals comparable to [START_REF] Johansson | Risk Assessment Model Applied on Building Physics: Statistical Data Acquisition and Stochastic Modeling of Indoor Moisture Supply in Swedish Multi-family Dwellings[END_REF][START_REF] Pallin | Stochastic modeling of moisture supply in dwellings based on moisture production and moisture buffering capacity[END_REF] (Table 3). Experimental data [START_REF] Johansson | Risk Assessment Model Applied on Building Physics: Statistical Data Acquisition and Stochastic Modeling of Indoor Moisture Supply in Swedish Multi-family Dwellings[END_REF][START_REF] Pallin | Stochastic modeling of moisture supply in dwellings based on moisture production and moisture buffering capacity[END_REF] cited in [52] -for 3 people 2.4 kg.day -1 (average 33 g.h -1 per person) [START_REF] Woloszyn | The effect of combining a relative-humidity-sensitive ventilation system with the moisturebuffering capacity of materials on indoor climate and energy efficiency of buildings[END_REF] s Finally, a review on the indoor moisture also showed sources ranging from very simplified to more realistic sources [START_REF] Labat | Moisture balance assessment at room scale for four cases based on numerical simulations of HAM transfers for a realistic occupancy scenario[END_REF]. The simplest is an average constant emission based on [START_REF] Walker | Humidity Implications for Meeting Residential Ventilation Requirements[END_REF] which reviewed nine studies, suggesting the average emission of 270 g.h -1 to be used for a 1-year simulation. This review [START_REF] Labat | Moisture balance assessment at room scale for four cases based on numerical simulations of HAM transfers for a realistic occupancy scenario[END_REF] also showed that several experimental and numerical studies preferred using typical cyclic schedules. Lastly, stochastic scenarios could also be used, as demonstrated by [START_REF] Page | A generalised stochastic model for the simulation of occupant presence[END_REF][START_REF] Parys | Coupling of dynamic building simulation with stochastic modelling of occupant behaviour in officesa review-based integrated methodology[END_REF] in office buildings. For a one-zone experimental building, [START_REF] Labat | Moisture balance assessment at room scale for four cases based on numerical simulations of HAM transfers for a realistic occupancy scenario[END_REF] showed how constant emission rates could result in increasing the comfort range by 10-20%, compared to the use of stochastic scenarios.

Analysis and scenario proposals

First of all, all the metabolism moisture emission rates in the literature reviewed are within the same range, so we suggest using the moisture generation rates for the metabolism emission of 55/40 g.h -1

(awake/asleep). Next step is to quantify the dispersion of moisture emissions rates due to activities, given in Table 2. In order to compared them, we calculated for each reference ([34]-A, [START_REF] Cen | Ventilation des bâtiments -Conception et dimensionnement des systèmes de ventilation résidentiels[END_REF]-B, [START_REF]Prénom) CEN, EN 15665 -Ventilation for buildings Determining performance criteria for residential ventilation systems[END_REF], [START_REF] Ccfat | VMC Simple Flux hygroréglable -Règles de calculs pour l'instruction d'une demande d'avis techniques -GS14.5 -Equipements / Ventilation et systèmes par vecteur air[END_REF], [START_REF] Pallin | Stochastic modeling of moisture supply in dwellings based on moisture production and moisture buffering capacity[END_REF]) the related daily moisture emissions, assuming one or five occupants, taking into account metabolism, cooking, showering, laundry and clothes drying. We assumed one laundry, one clothes drying per person and per week, and we calculated an average weighted emission rate per day. Lastly, we compared the calculated results expressed as an average emission rate in kg per day to the thresholds given in TR 14 788-C [START_REF] Cen | Ventilation des bâtiments -Conception et dimensionnement des systèmes de ventilation résidentiels[END_REF] (Table 4,Table 5). From these tables, we can observe that no standard gives high emission rates, and that these are in most cases low, and become medium if we consider five occupants. 2.6 X --EN-15-665 [START_REF]Prénom) CEN, EN 15665 -Ventilation for buildings Determining performance criteria for residential ventilation systems[END_REF] 1.4 X --CCFAT, 2015 [START_REF] Ccfat | VMC Simple Flux hygroréglable -Règles de calculs pour l'instruction d'une demande d'avis techniques -GS14.5 -Equipements / Ventilation et systèmes par vecteur air[END_REF] 1.6 X --14 [START_REF]Prénom) CEN, EN 15665 -Ventilation for buildings Determining performance criteria for residential ventilation systems[END_REF] 4.9 X --CCFAT, 2015 [START_REF] Ccfat | VMC Simple Flux hygroréglable -Règles de calculs pour l'instruction d'une demande d'avis techniques -GS14.5 -Equipements / Ventilation et systèmes par vecteur air[END_REF] 7.9 -X -Experimental Data [START_REF] Pallin | Stochastic modeling of moisture supply in dwellings based on moisture production and moisture buffering capacity[END_REF] 5.2 X --Consequently, for our analysis, for the activity emissions, we suggest using the TR 14-788-A [START_REF] Cen | Ventilation des bâtiments -Conception et dimensionnement des systèmes de ventilation résidentiels[END_REF] data, because it is the most handicapping reference. We combined them with the emission duration

given by [START_REF] Johansson | Risk Assessment Model Applied on Building Physics: Statistical Data Acquisition and Stochastic Modeling of Indoor Moisture Supply in Swedish Multi-family Dwellings[END_REF][START_REF] Pallin | Stochastic modeling of moisture supply in dwellings based on moisture production and moisture buffering capacity[END_REF] because these data came from in-situ measurements, published in an IEA Annex and cited in [START_REF] Peuportier | Energétique des bâtiments et simulation thermique -B.Peuportier[END_REF]. The following moisture generation scenarios could be used:

-One shower per person per day, with an emission of 1440 g.h -1 for 10 min per shower;

-Cooking periods per day: 1512 g.h -1 for breakfast for 15 min; 2268 g.h -1 for lunch for 30 min; 2844 g.h -1 for dinner for 40 min;

-One laundry per person per week: 252 g.h -1 for 2 h; -One laundry drying per person per week (same days): 136.8 g.h -1 for 11 h.

This results in an average production of 6 kg.day -1 for five occupants, which is a rather low emission scenario.

Experimental Data [START_REF] Pallin | Stochastic modeling of moisture supply in dwellings based on moisture production and moisture buffering capacity[END_REF] 2.0 X --

Carbon dioxide

Emission rates in the literature: analysis and proposal

CO 2 emission rates are due to occupant metabolism and depend on the occupants' size and activity.

The literature gives the same order of magnitude and generally proposes making a difference between asleep and awake times, adults and children, as summarised in Table 6, which shows a quite good consensus around the value of 18 L.h -1 for an awake adult with a low level of activity. For a sleeping adult, the emission rates vary between 10 and 16 L.h -1 . Given this data, and as we are at the design stage of a building with generally no idea of occupant age, we considered that all occupants are adults, as explained in the above section. Finally, we used the emission rates proposed by Persily [START_REF] Persily | Evaluating building IAQ and ventilation with indoor carbon dioxide[END_REF]: 18 L.h -1 and 15 L.h -1 for an "awake" or "asleep" occupant of a residential building. The first value shows quite good consensus and the second allows one to avoid over-estimating ventilation performance.

Formaldehyde

Formaldehyde emission rates

General considerations

For formaldehyde, several authors have highlighted the correlation of concentrations and emissions with temperature, relative humidity and air exchange rates [START_REF] Park | Variations of formaldehyde and VOC levels during 3 years in new and older homes[END_REF]. Using a multivariate model fit on observational data testing temperature, humidity, the air change rate and outdoor concentration, [START_REF] Blondel | Screening of formaldehyde indoor sources and quantification of their emission using a passive sampler[END_REF] considered temperature to be the best correlated with the increase in the formaldehyde concentration. A chamber test study proposed a semi-empirical correlation law between the initial material's emittable concentration and the combined effect of humidity and temperature [START_REF] Liang | The combined effects of temperature and humidity on initial emittable formaldehyde concentration of a medium-density fiberboard[END_REF].

Moreover, the formaldehyde emissions of new houses from construction materials, such as wood products, are known to be constant for approximately nine months and then start to decrease [START_REF] Sherman | Formaldehyde as a basis for residential ventilation rates[END_REF],

to reach a steady state emission rate after a few years [START_REF] Park | Variations of formaldehyde and VOC levels during 3 years in new and older homes[END_REF].

Rates obtained in chamber-tested loads

The study reported by Plaisance et al. [START_REF] Plaisance | Characteristics of formaldehyde emissions from indoor materials assessed by a method using passive flux sampler measurements[END_REF] used a passive flux sampler for 6 h to define a linear equation between the formaldehyde mass collected and the emission rate of the tested material in a test chamber, according the ISO 16000-9 standard [38]. Depending on the surface tested, they calculated emission rates within the range [11.2; 682] g.h -1 .m -2 .

Several databases have been developed to verify such chamber-tested data. Pandora is a very large free-access database for indoor pollutant emission rates [START_REF] Abadie | PANDORA database: A compilation of indoor air pollutant emissions[END_REF], with more than 8000 emission rates from the literature classified by sources, including formaldehyde and PM 2.5 . Other databases were found such as the one developed in the EPEHCT project [START_REF] Missia | Literature review on product composition, emitted compounds and emissions rates and health end points from consumer products EPHECT project[END_REF] and the NIST Database [START_REF] Howard-Reed | Database Tools for Modeling Emissions and Control of Air Pollutants from Consumer Products, Cooking, and Combustion[END_REF], including formaldehyde. In these databases, formaldehyde emission rates for common materials can be found with a large spread, as for example for gypsum board (Pandora: in range [0.3; 42] µg.h -1 .m -2 ) or fibreboard medium (NIST: in range [14; 640] µg.h -1 .m -2 , Pandora: [237 -320] µg.h -1 .m -2 ). As a conclusion, the range of emission values is quite different from one database to another and the relationship with the in situ rates obtained in houses is complex.

In-situ rates obtained in houses

The EN-15251 standard [START_REF] Cen | EN 15251 -Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics[END_REF] provides two emission rates for formaldehyde: 50 g.h -1 .m -2 for lowpolluting buildings (glass, steel, rock) and 20 g.h -1 .m -2 for very-low-polluting buildings (without tobacco), considering the material surface areas. EN-16798-1 [START_REF]EN 16798-1 Energy performance of buildings -Part 1 : Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics -Module M1-6[END_REF] updates these emission rates to 100 and 50 g.h -1 .m -2 , respectively, based on the results calculated for the European Reference Room as specified in CEN/TS-16516.

A test conducted by [START_REF] Sherman | Formaldehyde as a basis for residential ventilation rates[END_REF][START_REF] Hodgson | Volatile Organic Compound Concentrations and Emission Rates in New Manufactured and Site-Built Houses[END_REF] was repeated three times on seven unoccupied prefabricated houses and on seven unoccupied site-built houses, located in eastern and southern USA, under two different climates, hot-humid and mixed-humid. The formaldehyde concentration was measured using two active samplers, inside and outside. The indoor sampler was located in the living/dining room 1.5 m above the floor. In addition, SF 6 was used as a tracer gas to measure the air change rates. The average constant emission rate was calculated from the average concentrations measured and the air change rate measured, using the mass conservation equation on the whole house considered as one zone. The result was an average emission rate of 44.17 (± 36%) g.h -1 .m -2 , considering the houses floor surface areas.

The study conducted by [START_REF] Blondel | Screening of formaldehyde indoor sources and quantification of their emission using a passive sampler[END_REF] took measurements of 24 student residence rooms with five different surfaces (flooring, ceiling and walls, doors, bed and other furniture), for three construction ages.

Formaldehyde concentrations were measured over 6 h with both conventional active samplers and passive samplers. Thirteen to 15 passive samplers were used per student room, with measurements taken in the room, in the common corridor adjacent to the room, and outside. Air change rates were measured using a CO 2 (tracer gas) injection method. Depending on the age of the building and the type of surface, the resulting average emission rates were within the range [1.4; 87.3] g.h -1 .m -2 , considering the material surface areas. Table 7 summarises all the emission rates reviewed.

Table 7: Overview of formaldehyde emission rates found in the literature

Analysis and scenario proposals

Few of these formaldehyde data are fully useful for a performance-based approach to ventilation.

We found either few or no data on average in-situ loads directly measured at the dwelling scale, and

Chamber-tested loads

More than 8000 emission rates from consumer products and building materials Pandora Database [START_REF]PANDORA Database[END_REF] EPEHCT project [START_REF] Missia | Literature review on product composition, emitted compounds and emissions rates and health end points from consumer products EPHECT project[END_REF] NIST Database [72] Chamber-tested loads especially in low-energy dwellings considered as representative. Consequently, the available data pose two problems:

-Firstly, it is difficult to extrapolate emission rate behaviours from test chamber conditions to in-situ conditions, notably because of the complex physical phenomena (combined effects, resuspension, etc.). As illustrated in Table 7, the order of magnitude of emission rates between chamber-tested loads in [START_REF] Plaisance | Characteristics of formaldehyde emissions from indoor materials assessed by a method using passive flux sampler measurements[END_REF] and in-situ loads in [START_REF] Blondel | Screening of formaldehyde indoor sources and quantification of their emission using a passive sampler[END_REF] varies by a factor of a 10 to 100.

-Secondly, it is difficult to build robust scenarios from the material, product and activity scale to the dwelling scale, as highlighted in [START_REF] Boulanger | QUAD BBC Project -Qualité d'air intérieur et systèmes de ventilation dans les bâtiments à basse consommation d'énergie[END_REF]. Indeed, due to the wide variety of materials available, the emission per m² of floor area varies from one building to another. In addition, the type of building materials and furniture and the quantities used (floor coverings, wall paintings, etc.) depend on the purpose of the buildings as well as on the design or construction methods used. Precise data are not yet described in scientific studies. In addition, emission rates for common materials are available with a high variability and even within the same type of material emission properties can vary considerably, as shown by the diversity of values presented in the databases [START_REF] Abadie | PANDORA database: A compilation of indoor air pollutant emissions[END_REF], [START_REF] Howard-Reed | Database Tools for Modeling Emissions and Control of Air Pollutants from Consumer Products, Cooking, and Combustion[END_REF] or as illustrated in [START_REF] Plaisance | Characteristics of formaldehyde emissions from indoor materials assessed by a method using passive flux sampler measurements[END_REF] for the Fibreboard medium 1,2,3. Consequently, arbitrary choices must be made to establish input data (using databases such as Pandora) for a detailed IAQ modelling at the scale of a residential building, as shown by [START_REF] Cony-Renaud-Salis | Analysis of the need of detailed modelling for the assessment of indoor air quality in residential buildings[END_REF].

We accordingly suggest using the simplified calculation method in [START_REF] Poirier | Development of Performance-Based Assessment Methods for Conventional and Smart Ventilation in Residential Buildings[END_REF] and applying it to unpublished data gathered on French low-energy homes to calculate average in-situ loads at the dwelling scale.

Based on these measurements, we define three classes of formaldehyde emissions to be used as input data for IAQ modelling, and for ventilation performance-based approaches at the design stage of low-energy houses:

-The low-emission class: 4.5 g.h -1 .m -2 , per m² of floor surface area, defined by the minimum calculated value; -The medium-emission class: 12.0 g.h -1 .m -2 , per m² of floor surface area, defined by the median calculated value; -The high-emission class: 23.6 g.h -1 .m -2 , per m² of floor surface area, defined by the maximum calculated value.

PM 2.5 particles

PM 2.5 emission rates in the literature

General considerations

The most widely studied PM 2.5 indoor emission sources are principally candle combustion, smoking and cooking activities. The emission values of hairspray [START_REF] Isaxon | Contribution of indoor-generated particles to residential exposure[END_REF] are usually occasional and relatively low, in comparison with candle combustion [START_REF] Bekö | Ultrafine particles: Exposure and source apportionment in 56 Danish homes[END_REF] or incense [START_REF] Afshari | Characterization of indoor sources of fine and ultrafine particles: a study conducted in a full-scale chamber[END_REF][START_REF] Géhin | Size distribution and emission rate measurement of fine and ultrafine particle from indoor human activities[END_REF], cooking activities [START_REF] Ji | Évaluation des expositions humaines aux particules ultrafines dans l'environnement domestique[END_REF] and smoking emissions. As described in the introduction, this work focuses on the assessment of ventilation performance, which should be seen as complementary to the reduction of indoor pollution sources.

Smoking is a significant indoor emission source but it is not included in this review because it is more relative to the performance of occupants than to ventilation system performance. The source of the emissions can easily be reduced by influencing the habits of the occupants. From this perspective, Borsboom et al. [START_REF] Borsboom | TN 68: Residential Ventilation and Health[END_REF] propose that tobacco smoke should not be considered in setting ventilation standards. A similar choice is made for candles and incense: they are related to habits and are excluded from our study.

Several studies showed that cooking is one of the most PM 2.5 -emitting activities [START_REF] He | Contribution from indoor sources to particle number and mass concentrations in residential houses[END_REF][START_REF] Abt | Relative contribution of outdoor and indoor particle sources to indoor concentrations[END_REF][START_REF] Long | Characterization of Indoor Particle Sources Using Continuous Mass and Size Monitors[END_REF][START_REF] Tuckett | Airborne particles in the home[END_REF]. Ji et al.

[80] corroborated this, providing measurements in an experimental house to quantify occupant exposure to ultrafine particles. They directly calculated this indicator from concentration measurements using occupancy schedules, without calculating emission rates. Each source was tested at least three times, and the concentration was measured in three different spaces to quantify the impact of the pollutant on the entire dwelling. We could thus classify the source into four categories depending on its global impact intensity (high, medium, limited, low). This study highlighted that the largest sources were: cooking and extra-heating for the high-impact sources, the toaster for the medium-impact sources, and incense, cigarettes, and candles for the limited-impact sources. PM 2.5 concentrations and emissions were also strongly correlated with outdoor conditions, intensity and type of ventilation, air leakage level and deposition and resuspension conditions [START_REF] Abt | Relative contribution of outdoor and indoor particle sources to indoor concentrations[END_REF][START_REF] Long | Characterization of Indoor Particle Sources Using Continuous Mass and Size Monitors[END_REF][START_REF] Lai | Personal exposures and microenvironment concentrations of PM2.5, VOC, NO2 and CO in Oxford, UK[END_REF][START_REF] Morawska | The relationship between indoor and outdoor airborne particles in the residential environment[END_REF].

Given their mass, particle matter is deposited on surfaces by gravity and various common actions can resuspend these particles. Moreover, particle matter can be formed by a chemical gaseous reaction such as between ozone and terpene [START_REF] Rohr | Generation and Quantification of Ultrafine Particles through Terpene/Ozone Reaction in a Chamber Setting[END_REF].

Based on this first literature analysis, we retained only emissions from cooking activities to build the PM 2.5 emission rate scenarios. Two review papers on the chemical components of particle matters [START_REF] Abdullahi | Emissions and indoor concentrations of particulate matter and its specific chemical components from cooking: A review[END_REF] and their impact on cooking emission rates [START_REF] Torkmahalleh | Review of factors impacting emission/concentration of cooking generated particulate matter[END_REF] have recently been published.

Rates obtained in test chambers

A study was carried out in a 32-m 3 test chamber in a research laboratory to characterise emissions from various activities (frying, gas stove, smoking, vacuuming, heater, radiator, scented candle, pure wax candle) [START_REF] Afshari | Characterization of indoor sources of fine and ultrafine particles: a study conducted in a full-scale chamber[END_REF]. The PM 2.5 concentration was measured by two different particle counters: a condensation particle counter and an optical particle counter. The concentration was continuously monitored before, during and after all the emission tests. A tracer gas decay method was used to determine the air change rate, based on concentration measurements made continuously over 2h with a photo-acoustic spectroscopy device. Emission rates were lastly calculated through air change rate concentration measurements and expressed as particles per minute. Unfortunately, these emission rates in particles per minute cannot be used in cooking emission rate research, because conversion into mg.min -1 is impossible.

Finally, the recent study conducted by O'Leary et al. [START_REF] O'leary | Investigating measurements of fine particle (PM2.5) emissions from the cooking of meals and mitigating exposure using a cooker hood[END_REF] used a test-chamber protocol with controlled ventilation to very precisely measure the PM 2.5 emission rate throughout the cooking processes. The four meals selected for this experiment were based on typical European portions and food types from representative data, like the panel method [START_REF] Olson | Distributions of PM2.5 Source Strengths for Cooking from the Research Triangle Park Particulate Matter Panel Study[END_REF] or the Western cooking type survey conducted by [START_REF] Chen | Emission Rates of Multiple Air Pollutants Generated from Chinese Residential Cooking[END_REF][START_REF] Zhao | Emission characteristics of PM2.5-bound chemicals from residential Chinese cooking[END_REF].

Rates obtained in a lab kitchen

Firstly, the study of [START_REF] Buonanno | Particle emission factors during cooking activities[END_REF] characterised the particle emissions of several foods (cheese, chips, bacon) by testing the impact of the oil used (sunflower, peanut, olive), the cooking method (frying/grilling) and temperature. These cooking tests were conducted in laboratory conditions in an 82-m² kitchen using electric and gas stoves. The results show that the higher the cooking temperature, the higher the particle emission rate is, as shown with the 50-g bacon experiment; 0.52 mg.min -1 emitted with minimum power (171°C ± 17°C) versus 13 mg.min -1 with maximum power (242°C ± 5.2°C). Oil type may also influence the emission rate (chips, sunflower oil, 1.20 mg.min -1 ; chips, olive oil, 2.80 mg.min -1 ) and this confirms that grilling activities are the highest emission sources, especially with gas stove cooking.

Other in-situ studies focused on cooking only one food, e.g. [START_REF] Torkmahalleh | A controlled study for the characterization of PM2.5 emitted during grilling ground beef meat[END_REF] for the PM 2.5 emitted during the cooking of ground beef in a dwelling. In this study, the test conditions were set up to limit other indoor and outdoor emission sources, for example, by closing all the doors during the test period and ventilating before the experiment. The resulting measurements were divided into four rate ranges [3.3 µm >2.1 µm >1.1 µm >0.65 µm >0.43 µm] and the value retained was the total average emission rate equal to 44.9 mg.min -1 .

Recently, [START_REF] Kang | Characteristics of cooking-generated PM10 and PM2.5 in residential buildings with different cooking and ventilation types[END_REF] also measured the PM 2.5 and PM 10 generation rate in situ for cooking in an experimental building based on grilling and frying activities (fish, meat, egg). Measurements were taken for 30 min including the time for cooking the ingredients (fish broiling: 13 min; meat frying: 6 min; egg frying: 4 min; meat broiling, 3 min). The comparison of experimental building results [START_REF] Kang | Characteristics of cooking-generated PM10 and PM2.5 in residential buildings with different cooking and ventilation types[END_REF] between frying (deep frying meat, 2.14 mg.min -1 ) and grilling (meat broiling, 16.08 mg.min -1 ) confirmed that higher particle emissions come from grilling/broiling activities.

In greater detail, [START_REF] Chen | Emission Rates of Multiple Air Pollutants Generated from Chinese Residential Cooking[END_REF][START_REF] Zhao | Emission characteristics of PM2.5-bound chemicals from residential Chinese cooking[END_REF] tested 25 typical Chinese dishes in a domestic kitchen based on an online survey of 309 families to determine common cooking behaviours in China. A professional cook performed five cooking methods with gas stoves (stir-frying, pan-frying, deep-frying, steaming and boiling), varying the weight of the ingredients, the type of meat, the meat/vegetable ratio and the type of oil. Measuring the emission generation rate includes the use of cooking tools during the process, with doors and windows closed and ventilation systems turned off. They found that water cooking methods such as boiling [0.08 mg.min -1 ] and steaming [0.05 mg.min -1 ] produce fewer emissions compared to other frying cooking methods (stir-frying [2.56 mg.min -1 ], pan-frying[1.61 mg.min -1 ].

In-situ rates obtained

The oldest in-situ study was conducted by [96] in the 1990s on a panel of 178 residents in Riverside, CA (USA). The PM 10 measurements were taken with personal exposure devices; at the same time the PM 2.5 rates were measured in each house using indoor and outdoor stationary monitors for two consecutive 12-h periods. The monitors used were based on a PM 10 filter behind an impactor plate.

The PM 10 emission rate of cooking activities was estimated at 4.1 ± 1.6 mg.min -1 with 40% of the particles smaller than 2.5 µm, with 1.7 ± 0.6 mg.min -1 as the PM 2.5 cooking emission rate. Other sources excluding cooking and smoking were estimated to emit 0.093 mg.min -1 for the PM 10 fraction, with 20% smaller than 2.5 µm (approximately 0.018 mg.min -1 ) as PM 2.5 . This study identified smoking and cooking as the two main indoor particle sources and provides an estimation of cooking emission rates but without distinguishing cooking methods.

In Australia, PM 2.5 measurements were conducted on 16 houses [START_REF] He | Contribution from indoor sources to particle number and mass concentrations in residential houses[END_REF]. The concentration was estimated simultaneously with a condensation particle counter and a photometer (sampling time 10 and 30 s) over more than 48 h in the kitchen. Air change rates were measured with a tracer gas method using CO 2 during the unoccupied period. The emission rate was then calculated using concentration, air change rate, volume, and penetration efficiency and deposition rate. The authors published data on cooking, frying, grilling, toasting, smoking, vacuuming and other emission rates within the range [0.07; 2.78] mg.min -1 . The results confirm that cooking activities are the main PM 2.5 sources in dwellings, with high emission levels during frying and grilling activities. The concentration increased more than 30 times the normal background concentration level during frying and up to 90 times during grilling.

A study in the USA also took PM 2.5 measurements on 37 residential homes over 7 consecutive days for each of four seasons [START_REF] Olson | Distributions of PM2.5 Source Strengths for Cooking from the Research Triangle Park Particulate Matter Panel Study[END_REF]. Concentrations were monitored for 24 h inside and outside using a filter-based monitor. The air change rate was measured with a tracer gas method, using perfluorocarbon. The air change rate was calculated with a mass balance. At the same time, each occupant carried a passive sample monitor, collecting the personal PM 2.5 data every minute, and had to fill in a 15-min time-step schedule. This provided the occupants' location and activities so that emission rates of specific cooking actions (frying, grilling, toast, stovetop, burned) could be calculated with 36 mg.min -1 as the average value within the range of [10; 470] mg.min -1 .

Recently, an in-situ campaign was conducted on 30 residential buildings and one experimental building to characterise PM 10 and PM 2.5 generated by Korean cooking activities over 1 month [START_REF] Kang | Characteristics of cooking-generated PM10 and PM2.5 in residential buildings with different cooking and ventilation types[END_REF]. In the residential buildings the emissions of soup cooking, broiling and frying activities were measured for a total of 30 min including both cooking time limited to 15 min to prevent over-cooking and preparation time. The results were compared with Western cooking types [START_REF] He | Contribution from indoor sources to particle number and mass concentrations in residential houses[END_REF] [96]: Asian cooking gave slightly higher emission rate values within the range [0.39 mg.min -1 ; 20.54 mg.min -1 ] (Table 8).

Analysis and scenario proposals

We grouped cooking emission sources in four cooking types: boiling, frying, grilling and a total cooking category taking into account any food preparation (Table 9). As expected in the articles and confirmed by the minimum, mean, maximum and median values, grilling is the highest and boiling is the lowest PM 2.5 emission cooking type.

Table 9. Emission rate values

Finally, a few studies took into account the entire cooking process with several food types for a complete meal and the associated duration, especially for a representative French cooking scenario context.

Assessing ventilation systems and kitchen hood performance, the O'Leary study [START_REF] O'leary | Investigating measurements of fine particle (PM2.5) emissions from the cooking of meals and mitigating exposure using a cooker hood[END_REF] is particularly relevant and fits our overall performance evaluation approach for ventilation systems. It took into account all the cooking steps in a European context. The authors proposed meal 1, with the lowest emissions, with chicken and potatoes fried in oil and green beans boiled in water [0.62 mg.min -1 ].

Meal 3 with pasta bolognaise had an intermediary emission rate [1.9 mg.min -1 ]. Meal 4 had the highest emissions with fried chicken and vegetable noodle wok cooking [3.2 mg.min -1 ]. This gave three combinations of meal 1, 3 and 4 to propose three realistic cooking scenarios for 1 week:

-Low-emission cooking practices, with the hypothesis of 50% of the meals a week, emit fewer emissions, like meal 1, and the other 50% of the meals have medium emissions, like meal 3.

-Intermediate-emission cooking practices use diversified cooking methods, where the meal types are equally distributed over a week [1/3 meal 1; 1/3 meal 3; 1/3 meal 4].

Cooking type

Emission rate [mg.min -High-emission cooking practices, with the hypothesis that 50% of the meals a week emit a high level of emissions, such as meal 4, and the other 50% meals emit a medium range of emissions, such as meal 3.

These three scenarios are summarised in Table 10 as mean values repeated twice a day with a cooking duration of 28 min.

Table 10. PM 2.5 emission rate scenarios

Synthesis of selected occupancy and emission input scenarios

Figure 2 summarises the input data for assessing ventilation performance at the design stage of a building, classified into pollutant scenario data, moisture scenario data, and inhabitant occupancy data. For PM 2.5 and formaldehyde emission rates, we propose three classes of emissions: high, medium and low, to be selected depending on the available data at the design stage.

For formaldehyde for instance:

-If only A-class IAQ-labelled materials [START_REF]Compulsory labeling of VOC emission of all construction products and decorative products installed indoors[END_REF] are used and occupants are aware of this, the lowemission formaldehyde rate can be used in the IAQ calculation. To achieve a low emission rate, it is necessary to increase the occupants' awareness and help them become lowemitting occupants in all their activities and furnishings. Tools have been developed for occupants for this purpose [START_REF] Déoux | Guide Grand Air[END_REF]. An in-situ measurement campaign could also be required once the building is occupied to encourage the low emission rate.

-If no information is given, or only D-class IAQ-labelling materials are used, a high-emission formaldehyde rate must be used.

28

-In other cases, a medium-emission formaldehyde rate can be used.

For PM 2.5 :

-If the occupants are aware of IAQ , and their habits confirm they rarely use grilling, and if they agree with an in-situ measurement campaign once the building is occupied, a lowemission PM 2.5 rate can be used in the IAQ calculation.

-If no information is given, a high-emission PM 2.5 rate must be used.

-If the occupants are aware of IAQ, and their habits confirm they rarely use grilling, a medium-emission PM 2.5 rate can be used.

Figure 2. Selected input data to be used in a performance-based approach for ventilation.

Conclusion and perspectives

We need a performance-based approach for assessing ventilation performance at the building scale, at the design stage, like the regulatory energy performance calculation to ensure energy performance. Ventilation performance assessment is often based on CO 2 , moisture, as they are commonly used, and on formaldehyde and PM 2.5 as they would be complementary. To calculate such IAQ performance indicators, few occupancy schedules and emission rate parameters are available today. This paper provides an extensive literature review of 73 articles covering detailed occupancy schedules throughout the day and the year in a house, with emission rates reflecting occupants and activities (e.g. showering, cooking), as well as building material and furniture emission rates.

We found relevant data on occupancy schedules, even if most of them were not precise enough to provide information on occupancy in all the rooms in a house. Substantial relevant data on CO 2 and humidity emissions due to inhabitants' metabolism and activities are available in the literature and we selected those that could be used in a performance-based approach at the design stage. We noted a lack of exploitable data that could be used to model PM 2.5 and formaldehyde average and peak emissions at the dwelling scale. As a result, we proposed using three levels of constant emission rates for formaldehyde: the low-emission rate: 4.5 g.h -1 .m -2 ; the medium-emission rate:

12.0 g.h -1 .m -2 ; and the high-emission rate: 23.6 g.h -1 .m -2 . For PM 2.5 , we also proposed three classes of emissions for cooking activities associated with a 28-min period twice a day: the low-emission rate: 1.26 mg.min -1 ; the medium-emission rate: 1.91 mg.min -1 ; and the high-emission rate: 2.55 mg.min -1 .

Our objective was to build emission scenarios for a European, or even French, application.

Nevertheless, the data gathered in the present review, as well as the way of analysing them and constructing scenarios are sufficiently described and referenced here and can be easily adapted for applications in other countries.

We focused on long-term exposure but this approach should also be adapted to consider acute exposure, another topic of interest and a health concern.

As for the study's limitations, there is a lack of consistent emission data on both formaldehyde and PM 2.5 emissions at a building scale; consequently, the scenario proposals must be considered as a preliminary suggestion for overall ventilation performance assessment, which could be improved with further studies. The main objective of this work was to build a first baseline, directly usable in a method for assessing ventilation performance. Obviously, the proposed scenarios can evolve and be completed and improved in the future, as and when they are published, and according to the context of application in different regions or countries. One of the tracks would be to add relevant behaviours with other pollutant emissions, such as toasting toast for breakfast, for example, for PM 2.5 . Another would be to link formaldehyde emissions to a series of scenarios for materials and furniture depending on the type of building and occupants, when consistent data are available. In addition, it is also possible to extend the IAQ indicators by adding other pollutants, although this then adds to the knowledge of emissions data and complicates the indication of IAQ levels and the operational aspect of the performance-based approach.

Nevertheless, it is now possible to assess the ventilation performance at the design stage of a residential building from an IAQ point of view, using the proposed occupancy schedules and emission scenarios as input data. In future work, these scenarios will be applied in a standardised approach, by modelling ventilation systems and strategies, air inlets and outlets configurations, airflow rates, etc. Such a standardised approach will allow for example a relative comparison of the performance of classic ventilation strategies and innovative ones, as smart ventilation strategies. In order to help at the design stage, the method can be used to select a ventilation system that targets a level of energy and IAQ performance, to comply with an overall performance requirement, but also to achieve IAQ labelled products and even improve IAQ awareness among occupants.

Figure 1 .

 1 Figure 1. Performance-based approach for ventilation.

- 9 h

 9 20 min in bedrooms, -2 h 50 min in the living room, -2 h 40 min in the kitchen, -40 min in the bathrooms, -For a total of 9 h 20 min asleep, 14 h 40 min awake, 9 h outside and 15 h inside.

  14-788-B [34]

Emission rate scenarios for a ventilation performance assessment at the design stage of a residential building 4.1 Moisture

	4
			occupant -1 ]
	Sedentary adult	19	50
	Low physical exercise	50	200
	Medium physical exercise	100	430
	High physical exercise	170	750
	Children, 3-6 years	18	90
	Children, 14-16 years	19	50

Table 2 :

 2 Moisture emission rates of activities

	Activities	Emission rate	Duration	Reference
	Cooking /person
	-Breakfast
	-Lunch (weekend)
	-Dinner Shower (a) CCFAT / EN 15665 Laundry (b)

Table 4 .

 4 Comparing calculated daily moisture emissions with thresholds given in TR 14-788-C (CEN, 2006a), one occupant.

Table 5 .

 5 Comparing calculated daily moisture emissions with thresholds given in TR 14-788-C[START_REF] Cen | Ventilation des bâtiments -Conception et dimensionnement des systèmes de ventilation résidentiels[END_REF], five occupants.

		Reference	Calculated daily emissions [kg.day -1 ]	Low 6 kg.day -1	Medium 11 kg.day -1	High 15 kg.day -1
	occupants	TR 14-788-A [34] TR 14-788-B [34] EN-15-665	8.4 7.2	--	X X	--
	5

Table 6 :

 6 CO 2 metabolism emission rates

	Emission rates	[L.(h.person)	-1 ]	Sources
	Sedentary
	-3-6 years -14-16 years	18 19		[41]
	-Adult	19
	Awake Asleep	16 10		[35]+ [37]
	Awake/asleep
	-<2 year-old -10-to 13-year-old	8/4 12/8		Annex 27 IEA [40]
	->15-year-old	18/12
	Asleep, measured in occupied apartments
	-Child	13		[44]
	-Adult	16
	Child (medium exercise)	10
	Adult (office work)	18		[58]
	Adult (asleep)	15

Table 8 :

 8 Overview of PM 2.5 emission rates

	Cooking activities	Emission rate [mg.min -1 ]	Duration [min]	Reference
	Cooking (any food preparation using stove, no frying or grilling) Frying (any food preparation using frying) Grilling (any food preparation using grilling)	0.11 2.68 2.78	10	[13] In-situ loads
	Frying		8-10	[93]


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

(2) Zi-Kui Liu, Y. Austin Chang, Calphad, Vol. 23, No 3-4, pp. 339-356, 1999.

(3) I. Ansara, M. Selleby, Calphad, Vol. 18, No. 1, pp. 99-107, 1994.

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( Cobalt-base superalloys are currently used as bulk materials for parts of aeronautic turbines. These latter support mechanical and thermal constraints. As the lifetime of these parts is limited, the aim of this work is to elaborate new alloys with higher solidus temperature and mechanical resistance. The best way to speed up development of new materials is thanks to thermodynamic simulations (Thermo-Calc), which will propose solutions to choose the microstructure and the alloy elaboration process.

Prediction of phases equilibrium versus temperature and composition: Influence of C content on the Co-base superalloy microstructure.

Use of isothermal sections to select particularly high refractory materials

The following tables summarize the binary and ternary systems added to SSOL SGTE solutions database to build our own database : Prediction of an eventual solidus temperature diminution near the metaloxide interface due to a variation of the alloy composition.

  An example of thermodynamical calculations applied to the study of the high temperature behaviour of Co-base superalloys strengthened by tantalum carbides Sylvain Michon, Patrice Berthod, Lionel Aranda, Christophe Rapin, Renaud Podor, Pierre Steinmetz To cite this version: Sylvain Michon, Patrice Berthod, Lionel Aranda, Christophe Rapin, Renaud Podor, et al.. An example of thermodynamical calculations applied to the study of the high temperature behaviour of Co-base superalloys strengthened by tantalum carbides. Calphad XXXII, May 2003, La Malbaie, Canada. hal-04079345 Co-Ni-Cr Co-Cr-Ta Co-Ta-C Co-Ni-Ta Co-Cr--C Ni-Cr-C Ni-Cr-Ta Ni-Ta-C Cr-Ta-K. Frisk, A. Fernandez Guillermet, Journal of Alloys and Compounds, 238 (1996) 167-179.

  5) L. Dumitrescu, M. Ekroth, B. Jansson, Metallurgical and Materials Transactions A, Vol. 32A, pp. 2167-2174, 2001. (6) N. Dupin, I. Ansara, Z. Metallkd., Vol. 87, pp. 555-561, 1996. Laboratoire de Chimie du Solide Minéral -(UMR 7555), Université Henri Poincaré Boulevard des aiguillettes, BP 239 -54506 Vandoeuvre cedex, France An example of thermodynamical calculations applied to the study of the high temperature behaviour of Co-base superalloys strengthened by tantalum carbides S.MICHON, P.BERTHOD, L.ARANDA, C.RAPIN, R.PODOR, P.STEINMETZ

  In the cobalt-base superalloys reinforced by TaC, the best mechanical properties are related with :-a high solidus temperature -the absence of chromium carbides As a consequence, the optimum carbon content predicted by the phase diagram (on the right) is 0,38%w. The microstructures obtained (alloys 1 & 2) are in good agreement with the phase diagram calculation.These alloys were synthesized by induction heating and aged for 100 hrs at 1200°CThe comparison between the melting temperature predicted by Thermo-Calc with those determined by Differential Thermal Analysis shows a constant difference of about 50°C.The absolute melting tempe rature can not be reached by Thermo-Calc calculations. Nevertheless, these results obtained thanks to this software allow the alloys classification according to their solidus temperature.The solid domain predicted by Thermo-Calc is precise enough to elaborate alloys with the desired microstructure (-oxide interface (µm) Solid us Temperatu re (°C)Database constitutionIn our research fields, thermodynamic simulations allow: the prediction of the equilibrium phases to better select the chemical composition in order to obtained the desired phases (natures and quantities) to prevent the risk of apparition of undesirable phases (σ phase, TCP phases….)the selection of highest refractory materials to select an alloy with the solidus temperature as far as possible of the working temperature.the evaluation of local melting temperature to predict a possible minimizing of surface mechanical properties induced by the oxidation phenomena.

  07 19.89 1.05 0.25 300 bal 9.65 23.77 5.80 0.37 400 bal 9.42 26.59 5.80 0.37 * : By hypothesis, carbon content decreases linearly from the bulk to the oxide scale