PhD Suzel Balez
email: suzel.balez@wanadoo.fr

Characterisation of an existing building according to olfactory parameters

Olfactory interpretation is, most of the time, the combination of varied physical, chemical, physiological and sociocultural elements of odour. The paradigm of olfactory effect is one way to express some of these combinations which are among the most typical in building environment. The olfactory repertory presented here corresponds to the modes of appearance displacement and disappearance in space of the odour. When the concept is transferred to a field study, with the "commented city walk" method specifically adapted to olfactory sensation, some interactions between building environment, odours and the user interpretations can be highlighted. Theses "olfactory configurations" describe olfactory phenomena in their connections with technical or architectural devices. They can be, in the end, considered as models to integrate odour in building conception.

Introduction

Many works [START_REF] Schaal | MONTAGNER A et al Les simulations olfactives dans les relations entre l'enfant et la mère[END_REF] suggest that in most of human societies odour is a very important element, not only in inter-individuals relationship (especially in family), but also in the relationship between human beings with their life areas. A research made during a PhD work [START_REF] Balez | Ambiances olfactives dans l'espace construit, Perception des usagers et dispositifs techniques et architecturaux pour la maîtrise des ambiances olfactyives dans les espaces de type tertiaire[END_REF] shows that nowadays, odour is perceived as an intrinsic element of animate and inanimate things themselves. So it is supposed to be a palliative to vision limits. Now the invisible is very present in some aspects of our society, for example in global air quality or cleanliness evaluations. They are all the more estimated through odour, since their imagery seems so be very influenced by the 17's miasma theories [START_REF]Le miasme et la jonquille[END_REF] which used to ascribe sanitary danger to putrefaction odours. Although indoor air control is currently an important preoccupation in buildings management and conception, it is relevant that its olfactory aspects are almost forgotten. In fact odour is still hard to interpret. So how can one observe its role as ambient factor in environment, and then take it into account in building conception?

The first studies about odour in environment are many centuries old [START_REF]Le miasme et la jonquille[END_REF], but it is still a topic to be ameliorated. The knowledge of all varied odorous molecules from a smelling miscellany is not sufficient to deduce the resulting odour because science doesn't master the knowledge of the mixing rules yet. So the methodological tools for olfactory environment evaluation are not full. The field studies have difficulties to make the connection between odour concentration and perception intensity account. This connection is different not only for each odour but also for each component of the odour. The distance from the olfactory source, influencing components concentration, can thereby considerably change the olfactory perception quality . The only snag with the current field approaches of odour in environment is that is focus on the olfactory nuisances. But it is a contestable approach which limits the observation and then the intervention field on the smelling environment because it can only lead to "fight against" strategies. Considering building environment odours is going past the reductive notion of nuisance.

To do so, we prefer a phenomenological approach of in situ odour. Thanks to an analyse tool, the olfactory effects repertory, and with an odour adapted method, some olfactory phenomena in existing buildings can be understandable.

The olfactory effect, a repertory

The olfactory effect is a conceptual tool linking up different knowledge fields [START_REF] Balez | Ambiances olfactives dans l'espace construit, Perception des usagers et dispositifs techniques et architecturaux pour la maîtrise des ambiances olfactyives dans les espaces de type tertiaire[END_REF][START_REF] Augoyard | A l'écoute de l'environnement : répertoire des effets sonores[END_REF]. On the theorisation model of ethology, some transversals have been stretched into diverse currently aspects of wisdom and the results of an enquiry about ordinary olfactory perception in building environment. These transversals enable to pay no heed the current gaps of knowledge on odour because they to lean on olfactory phenomena as they are described by users. The 32 olfactory effects already defined are organised1 in 5 classes presenting commons schemes.

1.1.

Elementary olfactory effects Odour is a chemical signal arisen out of our environment, from animate and inanimate things around us. It's part of their escaping substance that we pick up and interpret. The olfactory phenomena links to the propagation of this signal in building environment can be expressed by the elementary olfactory effects. The odour diffusion conditions in a volume of air depend widely on its volatility and especially on the distinct volatility of its diverse components. First, the most volatile molecules are principally emitted. Then, in a closed area, the air is slowly getting saturated by all the components of the odour. Theses phenomena can be described with the static diffusion, invasion and concentration effects. If there are some air movements, the olfactory homogenisation is faster (dynamic diffusion effect). Some environmental conditions such as heat improve components emission in the air. It can thereby induce changes in the odour aspect, modifying its components proportions (warp effect). Some materials with specific proprieties can also absorb a loss of these odorous volatile components, to release them later into another atmosphere (permeation effect). When the olfactory emission ceases, as fresh air comes, the odour components go out in their order of appearance (disappearance effect).

Composition effects

The smell sense has very important discrimination abilities, at low concentration. It is also organised in "stereo", so the localisation of odour sources becomes easier. The composition olfactory effects can describe the space arrangement possibilities. They depend widely on the space-time devices of the odour diffusion, for example, during the moving of people in the surroundings of odour sources, in abrupt meetings with odour or in increasing or decreasing odour intensity gradients (irruption, crescendo and decrescendo effects). When the odour source is moving, it let a specific trace behind itself (wake effect). If many odour sources are (or had been) in the same volume, their odours can be perceived as separate clusters, because they are very localised in space or because their chemical nature and/or their perceptive identification need that the "smeller" distinguishes them (arrangement and superposition effect). These odours can also be mixed, most of the time because they have similar volatility aspects ; then they are perceived as a whole (chord effect).

Mnemo-perceptive effects

The odour and its source can be sharply dissociated in space and time, so that the users have to make a double reconnaissance, both identification and space at a time (and also time) localisation of the (probable) odorous stimuli perceived. The mnemo-perceptive olfactory effects allow the description of this perceptive and mnemonic organisation in the reality. The tiredness and recovery of the sense of smell plays a crucial role in the everyday olfactory sensation since the furtive, repeated or extended contacts with various odorous volumes conditions the place apprehension (adaptation, recovering and repetition effects). In the same way, the odour sources localisation possibilities in space depend, for a large part, on the "smellers" movements, because the olfactory dispersion often gives an odour "immersion" feeling (ubiquity effect). If the odour source is localised enough in space and time, then its position can be located (localisation effect). Air movements can also lead to spatial localisation mistakes (miss-localisation effect). On the contrary, air inertia can delay the olfactory detection (time lag effect). The "smeller" can also be mistaken about the odour source identification (confusion effect). Odour can also generate a great reminiscence. This effect can be illustrated by the famous Proust's "petite Madeleine" episode (anamneses effect). This strong link between odour and memory has two consequences. On the one hand it can make a previous liked odour become hated after a bad experience (inversion effect). On the other hand it can make an odour become a spatial or temporal mark for people who smell it in a repetitive way (recurrence effect).

1.4.

Psycho-motions olfactory effects Air movement, as people movement, play an essential role in olfactory sensation in building areas. But odour can also set people in action (giving a ghost of motion or real move). Theses situations, when olfactory sensation cooperates with people motion are described in four psycho-motions effects. Since other people's odours if too close can be felt as an aggression, the personal interindividuals interactions "bubble" seems to have an odorous dimension (imposition effect). So the odours often make people act. It can be a run away, a polarisation or a systematic surveying of space (repulsion, attraction and zigzag effects).

1.5.

Semantics olfactory effects In the long philogenetic story where the sense of smell is included, the principal function of the olfactory signal is to be informative. The semantics olfactory effects allow describing situations when the game between odour emergent signification and real context is a part of the way people interpret the situation. In spite of the current progression to the olfactory abstraction (perfume and its applications), the link between the objects smelling and their odours is still very strong. Some odours can therefore be exclusively or relatively attached to some specific beings, objects or places (icon and qualia effects). In the same way, when the odour source is not visible, odour identification can give information about an occurring or past event, except if there is a miss identification (pretence effect).

The current knowledge about odour insists on the chronobiological context in the hedonic olfactory interpretation (positive or negative judgement), but our work [START_REF] Schaal | MONTAGNER A et al Les simulations olfactives dans les relations entre l'enfant et la mère[END_REF] brings out the pound of the spatial-time context in this judgement. Users make a parallel between the semantic of odour (its signification) and a reference olfactory idea and estimate their coherences or incoherencies. When odour signification and the place and / or the moment it is smelled seem to be in contradiction, the situation judgement will be humorous at the best and negative at the worst. In this last case odour shall get a nuisance grade.

Theses olfactory effects definitions don't always lean on varied disciplinary fields in account owing to the many lacks in olfactory data. In spite of this heuristic part, these definitions make a synthesis about odour interpretation in context, its apparition, disappearance and transition modes in building areas. The olfactory effect is a first step for the olfactory phenomena analysis in building environment, so important for spaces makers. Therefore we used this repertory to analyse user's words in a fieldwork. Thanks to the city walk method [START_REF] Grosjean | observer une ambiance ? Les cahiers de la recherche architecturale[END_REF] adapted for odour and to this repertory, we have been able to characterise some olfactory phenomena in an existing building (a shopping centre).

A fieldwork

2.1.

Three corpus to collect and confront Thibaud's city walk method consists in walkers taking a stroll. The description of what they perceive and feel during the walk is recorded. They where asked, in our case, to focus their words on their olfactory sensations. Theses descriptions were then analysed, using the olfactory effect to have a lecture of the olfactory phenomena described. This allows hypothesis on the specific olfactory phenomena of the studied site. Then, to put the walkers words in context, this hypothesis were confronted to the materialistic data of the building (measures, ethnographic observations…). It allowed to understand them in their physical (signal, architectural environment), temporal and social (uses) contexts and therefore to establish some of the olfactory configurations of the site. The speech of users walking in the building as far as their olfactory sensations are concerned are most profitable. In order to understand the olfactory phenomena evoked in the best conditions, the materialistic and odour conditions analyse of theses descriptions have been done. The potential odour sources and their location, then the air conditioning device and especially air vent have been spotted. The qualitative and quantitative olfactory analyses of diverse zones have been done by a specialised jury using the field of odours [START_REF] Et Doré J-C | The field of odors : Toward a Universal Language for Odor Relationships[END_REF] collection of 45 pure odour references and organised in a three dimensions space. This kind of odour characterisation is mainly used in food and materials industries. After the learning (facilitate by its organisation), any odour can be described using the odour references. The studied building is a shopping centre in Grenoble (France). It is 2 parts composed, come through by a rectilinear gallery connected to another one facing a supermarket (fig. 1). The twelve recorded walkers had been chose with a familiarity degree with the building varied as possible. From people knowing it very well (as saleswoman…) to people coming in for the first time. The olfactory characterisations made by the specialised jury allow to figure out walkers' talk's conditions. The common olfactory background of the building was very hard to be described, because olfactory sources objects were missing as references to the walkers. The jury's characterisations lit the general odours chord in this shopping centre as a pyrogenous, grass and sulphured assemblage (fig. 2). In fact, the odour sources evoked by the users of the The spotted referents broadly correspond to persistent odors (pyrogenous and sulphured). They largely tally with food odors. For example, the pyrazine (42) is the dominant referent of the characterizations, yet the pyrazines appear when there is burning (Maillard reaction). The dimethyl sulfide (44) and diallyl sulfide (45) are present in many vegetables and in some fruits. The human bioeffluents are also evoked in this profile, by the methional (43) and the diallyl (45) again (sweat), by the butyric acid (8) (excrements, vomit), and by the dimethyl again (excrements). The most spotted referents also evoke some materials. As plastics ((29), ( 11) and ( 5)), wood (34) and "dusty" earth (37) only in a part of the building.

building essentially tally with food production (cooking, burning, frying…) and this olfactory profiles fit well with this kind of sources. So it is probable2 that the olfactory profile established trough the Field of Odours be relating to the diverse cooking activities distributed in all the building.

The jury of expert made also some intensity evaluations with the Odour Impact Meeting Scale [START_REF] Et Doré J-C | The field of odors : Toward a Universal Language for Odor Relationships[END_REF] (fig. 3)

In the walker's talks, the most odorous places are the food shops (at noon) and the shopping centre gates. The olfactory profile of the whole shopping centre at noon presents as a matter of fact important differences with the other profiles and above all its relative intensity is higher than in the morning or in the afternoon. Moreover, the gates haven't got an especially strongest intensity (comparing to other places in the building). The only exception is the A Figure 3: Example of relative odors intensities during a walk through the shopping center, in the morning, at noon and in the afternoon. The different levels [START_REF] Et Doré J-C | The field of odors : Toward a Universal Language for Odor Relationships[END_REF] combine qualitative effects to the simple intensity. They don't take an eventual familiarization account. (The other levels are: 7 -« undeniable » odor polarizing subject's mind. 8-Very powerful odor making the smelling difficult. The odor disagrees with the subject and others nerve terminations can be solicited. 9-so strong odor that it constrains the subject to limit its inspirations (less deep inspirations or research to put a way of filter to the nose. 10-To powerful odor to be tolerate, the subject search a way to escape from the olfactory source.)

The olfactory intensities of the first zone are for the most part lower than in the others parts of the shopping center. It's also at noon that the odors have the most important intensities. Weigh against the zone where it is, the A gate is an intense odors place.

Relative intensity level

No perceptible odor although a sustained attention

The subject perceive by a simple smell

The subject perceive the odor when he knows it and does a careful smelling operation Extremely low odor, not identifiable, although it's search in a fully knowledge of the note gate, where all the intensity evaluations are higher than in the same area at the over evaluation points. The walkers interpretations, often describing the gates (the way in) as strong odours places is therefore mainly induced by the big olfactory contrast between indoors and outdoors airs. The building gates are the place where irruption effects take place. The olfactory areas establish through the Field of Odours and the Odour Impact Meeting Scale presents a qualitative contrast between the different parts of the studied shopping centre, with an intensity increasing from one end to the other. This contrast in quality and intensity should be explored deeper, for example by more systematic measuring of all olfactory sources in correlation with all air moves. But such evaluations would come up against the knowledge lacks about odour (additionability, differential volatility) and about slow air movement in huge volumes.

Although the type of shops repartition is thereabouts the same, the user's words analyse shows a difference between the odours organisation of the different parts of the building. In some places, the chord effect seems to be the rule, a mix of non-designable odours, and the walker's odour descriptions are not much redundant. Moreover, in some places like the gallery facing the supermarket, even if the odour background is still present, the odour areas seem much constant. Yet the air conditioning devices of theses parts of the building are roughly different. The first ones have strong draught power stations, pretty faraway from each other, and the other littler power stations make a narrow gird pattern. This raises questions about air movements, more or less located, that could induce an odour stirring and/or zoning more or less strong. But this question bumps into the lack of measure or modelling tools for odour dispersion and for slow air movement in big volumes.

A synthesis: olfactory configurations (how it gives a comprehension of in situ olfactory phenomena)

Olfactory effects spotted in walker's words confronted with the information from the materialistic data gives a first approach of the olfactory phenomena of the site. But if an olfactory effect emergence often points out a cause, it doesn't necessarily raise it. And in the architectural or urban project odours management perspective, the only description of olfactory phenomena is not enough. It doesn't allow to think of materialistic interventions on the happening of the effect conditions. As a result, an olfactory effect is the departure of a

Physic-chemical Signal

field causal research. It drew our attention on the interactions between building, odour and user's sensation. The description of these interactions, for a given olfactory effect, forms an olfactory configuration. It is the expression of the interdependence relationships between the built object (trough it's architectural and/or technical devices), the user (its perceptive or using interpretations) and the odour (the nature of its sources, its physico-chemical proprieties) (fig. 4). The odour spreads in a building environment that may be odorous itself and which influences anyway its diffusion circumstances. The materialistic aspects of the built object also command, for a part, users comportment and users are themselves management actors of this spatial and technical environment. Be that as it may, these users smell and/ or emit the odour. They interpret it and the odour may, in its turn, influence their comportment.

So, in the field study used as reference, some olfactory configurations have been brought to light, on the base of the olfactory effect spotted in user's words and with the olfactory and materialistic data collected. For example, there was an unintelligible mix of odours in the studied shopping centre. This "odour fog" as it was called by some walkers, can be described as a chord effect, probably caused by a specific olfactory configuration. There was, in this building, really varied nature odours sources (olfactory dimension). Theses sources are spread in the building area, and the indoor air is stirred up by many devices. This makes the mix homogenization (spatial/ technical dimension) easier. At last, the users have difficulty to distinguish the little sets of the general olfactory maelstrom, because they don't want to or because they don't know well enough theses odours (perceptive dimension) (fig. 5).

The visit of the site modes also plays a role in the anticipation and olfactory familiarity of some place and moments in the shopping centre. Some odours (and their sources) have been in effect revealed as real spatial and / or temporal landmarks. The olfactory configuration of this repetition effect is the interaction of many elements. Theses odours have specific aspects and are very limited in space. The regularity of users visits induces also a memorisation and, consequently, a very good awareness of temporal and spatial particularities of the field.

The meeting with odour can also be progressive, as and when people move in the shopping centre. Especially when one goes up the shops gallery facing the supermarket, with a cooking/ burning odour getting crescendo. In this situation, the technical dimension of the configuration has still to be explored, but we can hypothesise that the crescendo is possible only if the air mix is not too strong compared to the power of diffusion and to the odour (Odors mix stimulatingly perceive, with no distinction or identification possibility) source intensity. This source has to be sufficiently intense and confined. In fact many ovens are gathered together at one end of the gallery (this situation is different from the organisation of the other part of the shopping centre with its very scattering ovens). To perceive this odour intensity growing, the walker's adaptation has to be "lower" than the stimuli. The fact is that people has to move into increasing odour intensity, i.e. to move to the odour source (fig. 6).

Chord effect

Olfactory configuration

Sometimes, the spatial organisation is responsible of specifically odour meetings modes. For example when the circulation space is becoming narrower, the interpersonal distances shorten, in other words walkers cross each other closer. So this proximity allows them to smell one an other, the spatial configuration encourages the waking effect (fig. 7).

The first contact with odour is a crucial moment of smelling perception. So the entries of the site are particularly propitious places and moments for olfactory apprehension of the shopping centre. It is where and when people instantly discover the common chord (the olfactory identity of the site) and some specific smelling sources, close to the gates. The olfactory dimension of this superposition effect configuration is due to very different smelling distances. The olfactory background of the site is a mix of various sources, not necessarily easy to distinguish ; this sources removal involves that only some of their compounds are 9m Shop Shop Shop Shop

4.8m

Wake effect perceptible (the other ones appear in too low concentration to be detectable). In other words, the odours of the most distant sources are not only mixed but also distorted. At the same time, there are often intense odours sources in the walker's proximity (the food shops, frequently very smelling, are concentrate at the gates proximity). Theses sources are, in addition, visible, which is probably helpful for the odours distinction and identification. The gates of the building are also an irruption effect place, witch corresponds to the brutality of the meeting with the indoor odour. This configuration is the result of the lack between the outdoor air (roughly consider as the odourless reference) and the smelling air of the building. The acting (coming in) walkers are not adapted to the indoor air yet and they there smelling is "full". A revolving door is in fact a device conceived to separate indoor and outdoor airs as much as possible, in order to avoid thermal loss. As a consequence, these two very contrasted smelling atmospheres are in contact but don't mix.

Olfactory configuration

Olfactory configuration

Conclusion

The olfactory configurations presented here are only a few examples among the ones this field enquiry allowed to reveal. They are the characterisation of some olfactory phenomena of the studied shopping centre, but they also are the first step for olfactory interventions in this field.

For example with the demonstration of the irruption effect mechanisms at the shopping centre gates, one can imagine ways to modify it, changing the materialistic, odours or uses dimensions of it. Transforming the air running of the building revolving door for example in pre-odorising it with indoor air, the actual irruption effect could be transformed in crescendo effect. The olfactory configurations of this site can be then regarded as interventions tools for the olfactory phenomena of the studied shopping centre, but they also have an ordinary dimension that can be transferred to this type of place and possibly to other type of areas. Some of theses configurations correspond to very specific dispositions of the site whereas some other are very general and could correspond to common phenomena in may spaces. So theses configurations present an exemplary character that could be taken into account in a project approach for this type of site. For example commercial identity is often an important preoccupation for the managers of this kind of places. One can imagine so that a specific odorisation, design from the different known configurations, could open the way to a control of olfactory identity of shopping places.

But the olfactory configuration notion is nevertheless limited, by its "sensory focus". The novelty of the subject towards architecture involves to be very focus on the smelling sense. But it is a very arbitrary choice that doesn't fit with the multi-sensoriality of the in situ real life. Some of the checked configurations highlighted by the way show the importance of vision in the olfactory apprehension. The chosen limits must be called into questions for the odour definition 3 because it seems to recover larger sensations in the current language (of the French people solicited). Anyway, theses configurations are typical of the interdependence relationships between odour, user and building. Because they take however the materialistic realisation principles of the phenomena they tend to orient account, they can be hence considered as models for any smelling architectural conception. The olfactory effect is therefore an analysis tool which, by the crossed knowledge it represents, allows to spot more than to characterise olfactory phenomena in building environment. After this first step, odour shall be, in the future, taken into account in architectural and urban conception.

Figure 2 :

 2 Figure 2: Three dimensions representation of the Field of Odors and of the common olfactory profile of the building. (The numbers correspond to the smelling referents (pure substances))The spotted referents broadly correspond to persistent odors (pyrogenous and sulphured). They largely tally with food odors. For example, the pyrazine (42) is the dominant referent of the characterizations, yet the pyrazines appear when there is burning (Maillard reaction). The dimethyl sulfide (44) and diallyl sulfide (45) are present in many vegetables and in some fruits. The human bioeffluents are also evoked in this profile, by the methional (43) and the diallyl (45) again (sweat), by the butyric acid (8) (excrements, vomit), and by the dimethyl again (excrements). The most spotted referents also evoke some materials. As plastics ((29), (11) and (5)), wood (34) and "dusty" earth (37) only in a part of the building.

Figure 4 :

 4 Figure 4: Principe of an Olfactory Configuration

Figure 5 :

 5 Figure 5: Olfactory configuration of a chord effect (the "odor fog" in the shopping center)

Figure 7 :(

 7 Figure 7: Olfactory configuration of a wake effect

Figure 6 :

 6 Figure 6: Olfactory configuration of a crescendo effect

  . It is mostly a

		n
			Supermarket
			X
			0	50 100 m
			Shops gallery
	Legend : nature of the mains odors sources
	Food:	burning	frying
	Materials:	furniture	(fancy) leather
		perfume cosmetic	pharmacy
		outstanding shop (soaps…)

X

Suzel Balez, Characterisation of an existing building according to olfactory parameter

5/11

This organization is based on the model of the sound effect repertory[START_REF] Augoyard | A l'écoute de l'environnement : répertoire des effets sonores[END_REF]

To establish a formal link between potential sources evoked by walkers and the shopping center's odors, some olfactory characterization should have been done potential source by potential source, yet we only characterize the building broads olfactory ambiances.

We have chosen to only consider detection by the smelling sense. So we didn't take what we call infra-odors and ultra-odors account in this research. Infra-odors are chemicals emit by a living organism and unconsciously detected by another one. It doesn't correspond exactly to pheromone. Pheromone definition's is essentialy given by its effects (influence fellows creatures in theirs physiology or in their comportment). A pheromone can be an odorant to. Ultra-odors are chemicals irritants perceive by the "pseudo-smell" perceptive systems like the trigeminal nerve.


Rachel Thomas -
email: rachel.thomas@grenoble.archi.fr

Dr Rachel Thomas Cresson

ARCHITECTURAL AND URBAN ATMOSPHERES SHAPING THE WAY WE WALK IN TOWN

Keywords: ambiences, body, urban public space, to walk, pedestrian

Starting from a simple question -what prompts us to walk in town?and an innovative methodological protocol we call the three-person walk -the author queries the implicit relations between the act of walking and atmospheres. How and to what extent do architectural and urban atmospheres affect our decisions when walking in town and influence a pedestrian's gait? By constituting two lexicons -one describing sensory configurations that are more or less favourable to walking, the other describing the types of relation possible between pedestrians and the city -the author makes two contributions to the debate on urban walking: first that there are many ways of walking; and secondly that we adapt our gait to suit -it is perhaps even shaped by -architectural and urban atmospheres.

What makes us walk in town?

With environmental concerns the focus of much debate, walking is becoming increasingly popular again in France and all over Europe. In the ideological battle with cars, urban walking has several obvious advantages: it consumes little energy and occupies less space; it is healthy; and it sustains social links. Despite this favourable context, the number of urban journeys made on foot is far smaller than those made in motor vehicles. We need to ask why but we also need to understand what makes us walk in town. Some engineers, transit-economists and policy-makers cite circumstantial or structural reasons to explain the small number of journeys on foot. Geographers and town planners prefer to focus on the determining factors for urban walking, highlighting the influence of urban morphology on modal choices. Whatever their merits both working perspectives all too often reduce the act of walking to its strictly motive dimension, restricting research into the conditions that make walking possible to just the built or developed qualities of towns. Our approach differs from these two lines of research. First, we consider walking as a social, sensory and plastic act. Walking in town brings pedestrians into contact with others, requires them to deal with bodies in movement and their proximity, anticipate eye-to-eye contact and so on. All these constraints implicit in walking, apart from those imposed by urban design, demand, on the part of the pedestrian, a number of navigation techniques [START_REF] Ryave | Notes on the art of walking[END_REF][START_REF] Livingston | Pedestrian Traffic Flow, Routledge and Kegan Paul, Making sense of ethnomethodology[END_REF] and body techniques (Mauss, 1954). When we glance forwards to anticipate the presence of the crowd, slide a foot across the ground to gauge the slope, or even dodge slightly to one side to avoid the crowd, we are indulging in forms of movement that make travel on foot possible and operational. Secondly, we assume that urban and architectural atmospheres impinge on modal choices and the way we walk in public spaces. With its tightly packed or empty places, and the activities they accommodate, and its materials, a town maps out spaces of visibility, listening, touching and so on, that may be plural, constrasting and changing. These urban and architectural atmospheres shape and modulate the way we walk, much as urban morphology or spatial design. Furthermore they contribute to the existence and expression of different ways of walking in town: walking is (…) often described as a unique form of locomotion and then contrasted with running; but attentive observation reveals that there are several types of walk, that the graduation between them is not continuous, but rather that each one his is own particular intensity (after [START_REF] Morris | La clé des gestes[END_REF]. From this point of view the quality of urban design is probably not enough to encourage us to walk in town. We need to explore the capacity of architectural and urban atmospheres to affect modal choices and shape multiform ways of walking.

This proposition was the focus of a Franco-Swiss research action recently funded by the National Research Agency (ANR)1 . Teams of sociologists, architects and town planners observed in situ the real walking practice of pedestrians. Work was guided by two assumptions. The first assumption posits the existence of heterogenous, variable ways of walking in town depending on sensory contexts: walking is not a generic category of travel on foot; it varies in its form, pace and expression as a function of architectural and urban atmospheres [START_REF] Thomas | Quand le pas fait corps et sens avec l'espace. Aspects perceptifs et expressifs de la marche en ville[END_REF](Thomas, , 2007)). The second assumption posits the existence of operational relations between walking and atmosphere: the nature of the relations established, by walking, between a pedestrian and the city may well impact on modal choices. This means we must qualify such relations and understand in what respect and how architectural and urban atmospheres can work as triggers for walking in town (Thomas, 2008).

The present article is divided into three parts. After reminding the reader of the methodology used for the purposes of this research action and the locations where it was deployed, we present two of the main results of our analysis 2 . The first result concerns the constitution of an exploratory lexicon describing a number of "sensory configurations" that are favourable, or unfavourable, to walking. The second hinges on the attempt to qualify "walking situations", describing the nature and intensity of relations between pedestrians and architectural and urban atmospheres.

The three person walk 3

This project required innovative methodological protocols, the purpose of which was not only to avoid disassociating the subject of research from empirical techniques but also to establish a dialogue between the accounts of heterogenous pedestrian routes. In this respect it meant "setting out on foot" in the field, observing and experimenting in the company of pedestrians various ways of walking in town (alone or with several others, strolling, passing through, hurrying, etc.) in order to gain a better grasp of the processes at work in pedestrian movement, the tiny modulations to which walking lends itself and the sensory "affordances" [START_REF] Gibson | The ecological approach to visual perception[END_REF] underpinning it. To this end an innovative methodological protocol was tested in four districts -two in Grenoble (France) and two in Geneva (Switzerland) : the "threeperson walk". This new methodology is based on the articulation of three complementary approaches which all give meaning to the subjectivity at work in the practices of city dwellers, and to the community of perceptions and feelings underpinning them.

Walking in the first, second and third-person singular -I, you, he or she

In the first-person ("I-walk"), the researcher is immersed in the study zones taking photographs at whim for half a day. He or she walks freely, without previously defining a route, drawn onwards by the terrain and atmosphere. A dictaphone is used to record passing impressions, in conjunction with a digital camera to fix noteworthy events, situations or vistas. Once this non-directional walk is complete the researcher produces a summary document in which the narrative and photographs bear witness to the route as it was perceived and feeled. The middle column in the table contains all the comments and photographs collected in situ. The column to its right isolates, for each place the various elements brought into play while walking. The classification of these elements into three categories -built, sensory and social -refers to the three dimensions of the urban environment that shape pedestrian practice: architecture and urban design; architectural and urban atmospheres; forms of public sociability. Lastly, the column to the left of the middle one, contains a lexicon of ways of walking in town. It was obtained by cross-referencing data analysed in the other two columns. In the second-person ("you-walk"), the researcher carries out a series of pavement interviews with pedestrians. Accompanying them on a portion of their journey, he or she questions them on the reasons for their journey, the choice of route and how they see the neighbourhood. A dictaphone is used to record their answers as they walk. If the person being interviewed agrees, the initial exchange at the end of the route may be extended, turning into a semidirective interview. In this case, the questions raised previously are explored in greater depth but it remains an open discussion so that the pedestrian is free to express his or her views. Speech is recorded during the walk, as for the first-person I-walk, using a dictaphone. About 60 people were interviewed in this way in France, the field location on which we have focussed analysis. These pavement interviews have helped to plot the routes taken on a map and serves as the basis for a transcription of the answers given pedestrians. This analysis has two merits. First it reveals the social and collective representations linked to each neighbourhood and the pedestrians' appraisal of its qualities. Secondly our analysis highlights the relation between personal motives that may prompt us to walk and the various conditions that enable walking actually to happen.

Lastly, with the third-person ("he or she-walk"), the researcher carries out "route reproductions". He or she follows unidentified pedestrians at a distance, paying attention to their practical actions (how they cope with the developed space, practical activities, stay in space…), their social conduct (how they handle encounters, the presence of others or a crowd), their body attitude (rate/rhythm of displacement, visual orientation, trajectory of the step.) and the events and characteristic of the crossed contexts. This sort of tailing, also recorded on a dictaphone, is transcribed in two ways: plotting on the map of the observed route; and a written description (gestures, trajectory, speed of movement, events, etc.) recorded in situ.

Example of a transcribed account of a route -Grenoble, Ile Verte

Route account n°11 -On Place du Grésivaudan, a woman who was on the left-hand side and has just crossed is now on the opposite side, walking towards La Tronche. She is carrying two loaves. She starts hurrying. She must be in her 70s. She crosses the road just to the right of the pedestrian crossing and enters a little side street, Rue Farconnet, which slopes gently downwards. She is walking on the pavement, but about 15 metres further along she steps into the road as if she was taking a short cut. Ten metres later she returns to the pavement, having taken a minor short cut at a bend in the street. She carries on walking along this very quiet street, going quite fast. There is a bin taking up almost all of the pavement, so she moves to the right but without stepping into the road. She carries straight on. She seizes something with her hands and looks up to the top of a building, then goes in (n°4).

We recorded 143 route accounts in France. Analysing them gives us a grasp of the way pedestrian mobility is modulated, in the dynamic of movement and depending on the context.

Europole and Ile Verte districts of Grenoble: two fields of experimentation

We experimented this survey protocol in Grenoble, in two districts: Ile Verte and Europole4. This was not a random choice: both districts have a strong identity in the town and enjoy direct links to the town centre (by car, tram and on foot). They also seem to lend themselves to walking (in that both have amenities dedicated to this form of travel), while offering very different, multiple conditions and settings for walking.

Map of the districts covered by the study -Manque échelle + nord

The Ile Verte (green island) district, located to the north-east of the town centre, is a setting that certainly impacts on the way pedestrians choose to travel. It is quiet and residential, organized around a network of often deserted streets, where the slightest presence attracts the interest of local people. The Isère river runs round more than half of the district's perimeter and paths have been laid out along the banks, attracting large numbers of people at weekends, walking, running and cycling. Over and above the significant role played by vegetation in the urban scene (extending into St Roch cemetery, referred to as the area's "green lung"), Ile Verte has a wide range of shops and services along the main thoroughfare, Avenue Maréchal Randon. This road is comparatively mineral in its make-up, with dense traffic, connecting the centre of Grenoble to the nearest suburb, La Tronche. Place du Docteur Girard, halfway along the avenue, has a surprising star configuration, now operating as a roundabout, with pedestrians, cyclists, cars and trams coexisting in considerable confusion demanding plenty of give-and-take on all sides.

Riverbank paths Deserted streets Avenue Maréchal Randon

Place du Dr Girard

The urbanscape of the Ile Verte district5

The Europole neighbourhood, located to the west of the city centre, is the new business district. Designed primarily for services (World Trade Center, law courts, international secondary school, graduate business school, etc.), much of the area is given over to recently built office blocks, in which steel and glass play a predominant part. Through its centre runs Rue Pierre Sémard, divided into two separate streams of traffic with a regular, reasonably peaceful flow of cars and trams. In this largely mineral environment, pedestrian use of public space corresponds to a regular and often rapid back-and-forth movement. They cross Avenue Doyen Gosse or Place Schuman, often without stopping, very probably taking advantage of these hygienic expanses (smooth surfaces on the ground and on the facades, no rough edges, high proportion of masonry) to keep their walking functional. The decor and atmosphere change as they approach Cours Berriat. This street marks the border between an old, working class neighbourhood, St Bruno, and the new business district. Cours Berriat reflects this mix: in the forms of transport (pedestrians, cycles, motorcycles, cars and trams all pass through here), in its population (a blend of classes and ethnic origins), and lastly in its trade (with restaurants, sandwich bars and a wide range of shops and services).

Pedestrians seem quite at home in this mixture and profusion, constantly adapting their behaviour to the micro-events that colour the location and make it attractive.

Avenue du Doyen Gosse Place de Sfax Place Schuman

Rue Pierre Sémard Cours Berriat

The mineral character of the Europole district

Each of these neighbourhoods thus had the benefit of viewpoints -by an outsider (researcher or one-off pedestrian testing the terrain) and an inhabitant -who, far from offering any opposition, contributed to a cross-referenced acquisition of the atmosphere and the various elements contributing to each neighbourhood's walkability.

The sensory configuration of walk

The analysis carried out as part of this research action shows that architectural and urban atmospheres contribute just as much to the choice of walking as the quality of urban design available to the pedestrian. Choosing to walk, over and above personal or passing motives, depends on the ability of a neighbourhood to embody multiple forms of spatiality. In other words, its capacity to prompt attachment or aversion, pleasure or fear [START_REF] Watson | Angoisse dans la 42 e rue, EHESS, Raison pratique : la couleur des pensées[END_REF], to allow meetings or the expression of a whole range of walking styles … are all qualities of the environment that weigh on the choice of walking and contribute to our attachment to a district. From this point of view, it is possible to identify some sensory configurations more conducive to travel by foot than others. By "sensory configuration" we refer to the result of the process by which pedestrians select, organize then shape the sensory material structuring their perception and action during the journey (Thomas, 2005). This restructuring of space, in the walking dynamic, should be understood as a "deformation of the built environment as it was designed and a recreation of the space through feeling and motivity" [START_REF] Augoyard | Step by Step. An essay in Everyday Walks in an Urban Setting[END_REF]. Six sensory configurations were identified: attractive, spreading out, mobilizing, suspensive, accelerating and inhibitive. Each one operates jointly or separately on motor action and affective level. In the following we present four configurations.

For example, the attractive mode encourages exercise through walking and triggers pleasure in the pedestrian. This sensory configuration is characterized by powerful, rhythmic sound, numerous visual openings and lively sociability. The combination of these characteristics not only contributes to setting a tempo for walking but also awakens the subject's senses. Caught up in and carried away by the atmosphere pedestrians adjust their gait to the pace of the place, listening to their surroundings and extending their visual attention. Bodily and perceptive immersion prompts a state of harmony that procures a feeling of pleasure and well-being. Strolling or ambling embody this pleasant relationship. Walking in this way, pedestrians are open to others and to outside events. In Grenoble Cours Berriat generally attracts walkers, despite significant design faults and dense, multimodal traffic. But this space, which offers many different views and is busy at all times, gives pedestrians an impression of leaving the town and being caught up in the rhythm of the place.

Cours Berriat -Grenoble Quartier Europole extended

The pleasurable feeling is also prompted by the suspensive configuration, but unlike the previous one it replaces walking with loitering or longer stays. In other words the suspensive configuration suddenly breaks the pace of progress, raising the pedestrian's perceptive acuity and reducing contacts with others: under the influence of crystal-clear or reverberating sound atmospheres, rough or slippery surfaces, a landscaped or stylized backdrop, the pedestrian stops walking and adopts a contemplative pose. In this case, the aim is to take the time to enjoy the environment's remarkable qualities. The public park and the square are common examples of this type of configuration, that is found frequently in the Ile Verte district. But the "suspensive" configuration can also be linked to the space having a particular functionality as a market, cemetery, tram stop or railway station, which can also encourage this variation in the pedestrian's pace and perceptive acuity. This is particularly the case as we pass through the railway station. This cube-like space, with large expanses of plate glass and a ground surface that is shiny and slippery, is characterized by a high level of sound and light reverberation. We observed three regimes of social interaction: short waits; long stays; and passing through. The combination of these qualities gradually reduces the speed at which pedestrians can move, forcing them to disperse their attention, which sometimes means they stop walking altogether.

The inhibitive mode is an illustration of the ambivalence of the urban development. In this case, places offer pedestrians ideal conditions for walking -wide, unencumbered pavements, smooth surfaces, agreeable night-time lighting, visual directionality, etc -but paradoxically they also make walking somehow inadequate. More exactly, walking it nevertheless makes the pedestrian feel ill at ease and out of place. Faced with an anti-septic environment the pedestrian feels foreign and, at the same time, exposed to the glances of local inhabitants. Moving through this vacuum, walking turns into flight, a brief crossing or a form of infiltration. In the first case the pedestrian suddenly starts to hurry. In the anguish of this precipitation their body shrinks in on itself, gestures become jerky, the torso and face turn downwards, bowed over in self-protection. In the two other cases the style of walking betrays a functional relationship with the surroundings. Crossing involves taking advantage of design features that facilitate faster progress and a more streamlined gait. Infiltration is a slower, more cautious way of walking, the aim being to enter a place discreetly while keeping watch for visual and sound events that may reveal another's presence. This configuration was observed on Avenue du Doyen Louis Weil, in the Europole district. The middle of this long, straight thoroughfare is occupied by two-way road traffic. On either side rise recently built office blocks and flats, often quite high and faced with glass panels, framing the distant landscape. At the foot of these buildings, wide pavements, clear of any obstacles and dotted with designer street lamps, await the occasional pedestrian, soon tired by this overly smooth environment.

On Avenue du Doyen Louis Weil I decide to venture as far as the international secondary school. The pavement is wide and comfortable, so as a pedestrian I feel at ease. Ahead of me rises the Chartreuse range. For the first time in Grenoble, I have the impression of being hemmed in, halted at the same time as being drawn towards the mountains. Their presence is not stifling. They resemble a goal to be reached, concentrating my gaze. Perhaps because in my immediate surroundings there is nothing really captivating. I walk down the avenue, which is almost deserted, going into the wind, which is unpleasant. The occasional car passes going one way or the other, in the middle of the street, looking for somewhere to park. The rare pedestrians I meet are walking slowly. Since leaving Place Schuman, I have been able to hear birds chirping, getting louder as I go on. They cover up the sound of the city. In fact I really get the impression I am outside the city, yet at the same time the facades of successive buildings along the avenue play a powerful role in the landscape, constricting the way I walk and where I look. I am not ill at ease, just bored. I look for a way out and decide not to carry on a far as the school.

Avenue du Doyen Louis Weil -Grenoble Europole

The accelerator is a powerful configuration in the Ile Verte district. The key characteristic of this configuration is that it speeds up pedestrian movement. This quality results primarily from a mixture of specific spatial properties: strict alignment of facades, high buildings and a broad thoroughfare affording visual prospects and giving the place a form of "directionality"; cadenced frequency of passing cars and/or trams, matched by the pendulum-like movement of pedestrians, giving the place a visual and acoustic rhythm. In the same way the sensory qualities of the space -and in particular its ability to confront pedestrians with sudden changes of atmosphere -contribute to the swift pace. As we walk through the Ile Verte district we perceive and cope with rapidly increasing and decreasing levels of noise, with variations in its source too, and the sudden appearance of a frame around the view. These characteristics, that are present for example on Rue de Mortillet, Rue Lachman or Avenue Maréchal Randon have a psycho-motive effect: they change the pace at which pedestrians walk and encourage them to adopt a more linear route.

Avenue Maréchal Randon -Grenoble, Ile Verte

For each of these sensory configurations the architectural and urban atmospheres consequently exert an influence on the two registers of walking, doing and experiencing. By providing pedestrians with a sensory basis for their conduct and awakening in them a range

The width of the avenue constitutes a visual and aeraulic opening to the outside of the town. The pavements are not in contradiction with the overall scale, but their repeated narrowing to allow for parking can be troublesome outside the shops opening onto the street.

After doing some neighbourhood shopping people go home to one of the smaller side streets in the vicinity, between the river and this thoroughfare. The wide avenue has a central reservation for the tram lines, and on either side a stream of road traffic -cars, buses, etc. This constitutes a major divide in the avenue, that is not easy to cross. Observing passers-by shows that attention focuses on the various crossroads, but the wish to cross somewhere other than the pedestrian crossingsparticularly as the avenue sometimes seems relatively empty -leads to risk-taking. A women with a stroller ventures out, counting on the kindness of a car-driver.

Here, there is a change of decor, a fairly abrupt shift in the atmosphere, with urban bustle, cars, trams and quite a high noise level. It all "takes hold" of me. I might feel out of place if I did not swiftly yield to the rhythm of the place. However something attracts my attention, an area slightly to one side where the urban bustle seems to have subsided momentarily. It is the sun-drenched terrace of a cafe, Le Grand Café, where a few people are taking their time over coffee and a chat. I watch them, wondering how comfortable they are, then concluding that the avenue displays a graduation in traffic rhythms: a break on the cafe terrace, a buffer zone formed by the pavement, the road and then the tram line.

of emotions, they contribute just as much to walking as does urban design. Furthermore they prompt ways of relating to the city that are probably related to our daily choice of a means of locomotion.

The intensity of walking situations

In other words, architectural and urban atmospheres also play a part in the intensity of the relationship between the pedestrian and the city. We may distinguish walking situations that reflect such relationships: paradox, opposition, adjustment, neutrality and conniving. These situations are neither predefined nor stable during an urban journey. They evolve, succeed or confront one another depending on objective material conditions, fuzzy, fluctuating sensory conditions, and the affective state of the pedestrian.

Paradox thus reflects an ambiguous relationship, a disparity between the (physical and sensory) contexts of walking and the pedestrian's (perceptive and emotional) expectations. This situation is observed in two specific cases. Firstly the quality of urban design fails to make up for the poverty and the unappealing atmosphere. Walking is chosen and the location traversed for strictly functional, practical reasons: doing shopping, going to a meeting or to work. In this type of context, walking does not become a set habit and another form of locomotion, less in keeping with the environment, may take its place:

Immersion on 6 April 2006: I "enter" the avenue walking along the left-hand pavement. The pavement is wide and comfortable, easy on pedestrians. Ahead the Chartreuse range rises, but it is not at all overwhelming, more a goal to achieve on which my gaze is concentrated. Perhaps too because nothing much in my immediate surroundings is really captivating. The avenue is deserted and I am walking into the wind, which is unpleasant. The facades of the building that line the avenue are very forceful in the landscape, a constraint on the way I walk and where I look. I am not ill at ease, just bored, looking for a way out.

In the other case the quality of the atmosphere makes up for the shortcomings of the design and makes the place genuinely attractive. With the prospect of various routes, a pulsating sound atmosphere, an open visual field that excites the senses, instils a feeling of freedom and well-being, and contributes to the overall good mood. Pedestrians really settle into this environment, to such an extent that they frequently walk through here or turn a simple walk into a pleasant stroll :

Immersion on 20 April 2006: the thoroughfare is immediately attractive. There is a quiet bustle of activity on the shaded left-hand pavement: young people around a cash point, others sitting outside a café, passers-by, cyclists, trams. There are not many cars at this time of day. The contrast between sunlight and shade, that one cannot fail to notice, is both an invitation to take sides and an ingredient all the way along the route in some ephemeral spatiality. I am inclined to start by walking along the street, without hurrying, fitting in with the easy-going springtime mood, then perhaps to digress.

A relation of complicity occurs when the expectations of pedestrians and the sensory quality of a space converge. In practical terms such complicity is fostered by the co-existence of attractive urban atmospheres and amenities that facilitate walking. Smooth or green environments that are peaceful and away from the urban drone, such as the small protected enclaves one may find in town centres, favour a feeling of freedom with scope for investing the place and a sense of ease in pedestrians. In addition to this attractive side, these sensory configurations have the power to suspend the rhythm of walking, giving pedestrians an opportunity to slow down or stop for a while. The peaceful atmosphere of parks and squares may nurture such a relation, but some contemporary spaces may also lend themselves to such complicity. Mineral areas with smooth, reverberating spaces, intermediate spaces with only sparse urban furniture, and recently refurbished historic sites sometimes become, for some time, places of intimacy or play where contacts may occur, with other people and with the fabric of the place. The relation of complicity between pedestrians and urban atmosphere gives rise to quite different types of walk. People may be seen strolling through shopping streets and parks. This relationship is characterized by less vigorous use of the body, glances cast in all directions and a greater inclination to listen to new sounds. Strolling is a particular form of slow walk which does not visibly imply any desire to reach anywhere (after [START_REF] Morris | La clé des gestes[END_REF].

Strolling is an aim in itself, a way of observing the urban scene just as much as a way of enjoying the city's shifting moods. Urban glide [roller-blading, skateboarding, etc.] is a special case and probably linked to the development of a style of contemporary architecture with few affordances, a fabric dominated by fluidity, as the city is embodied in a stripped-down plasticity. Urban glide differs from strolling in its speed, in its stylized postures and its repeated friction with textures. Leaning forward, looking far ahead, arms swinging beside the body, the pedestrian penetrates the air, brushes against or catches on available surfaces the better to push through space. Mobile among the mobile, those who glide are in some sense archetypal figures in the contemporary urban world where fleeting relations rule.

Adjustment, though similar to complicity, differs noticeably. On the one hand, complicity is characterized by harmony, adjustment is more a matter of conforming. In other words when this relation is engaged between pedestrians and the urban environment, it depends more on functionality and neutrality, than on affects or affinity. On the other hand, although atmosphere plays a key role in complicity, urban design is a major factor in adjustment. This betrays a strictly practical relation between pedestrians and the city. It reflects not so much the pleasure of walking as its adaptation to the pedestrian's goals and the scope it offers for taking advantage of the qualities of a given space. This relation of adjustment between the pedestrian's goals and urban atmospheres is reflected in a particular type of walk: crossing. Crossing a space, means passing through, making tracks across it either by necessity, or because it is on a route taking the pedestrian from point A to point B. Like urban glide and flight, crossing is a type of swift walk: the goal for pedestrians is to complete the trip efficiently, taking advantage of spatial components to speed up their pace and give greater direction to their progress. In this type of walk, pedestrians adopt a form of behaviour that is stylized but less flexible than for urban glide: the bust is thrust forwards, the gaze switches constantly between the far distance and the ground in front, and the ear is alert to any remote sounds that may indicate a change of bearings. Every aspect of pedestrians' behaviour and attention to urban atmospheres their walking savvy and ability to anticipate.

As for induction, it reflects a relation of causality between the pedestrian and urban atmospheres. In this type of relation pedestrians' behaviour and attitude are directly shaped by the sensory qualities of the spaces through which they pass. The "efficacy" of architectural and urban atmospheres is expressed in heterogonous sensory configurations. Some atmospheres mobilize (ie set in motion, make more mobile) the pedestrian's pace and attention to such an extent that they sometimes require an adjustment of gestures, the rhythm of movement and/or, less usually, the actual route. Thus, mobilizing places are often homogenous in terms of the buildings, laid out in straight lines with a linear perspective.

Framing of the view and minerality are two other characteristics. Most covered arcades or passages act as mobilizers. Other types of sensory configuration contribute to a relation of induction. But as well as mobilizing pedestrians' pace and attention, they contribute to distributing and spreading them in space and time. In many cases they are in fact nodes, joining or articulating several spaces. In addition to offering pedestrians a choice of routes they are characterized by two noticeable sensory qualities: a high noise level, in conjunction with a wave effect; one or more lines of visual flight, allowing pedestrians to anticipate at some distance the route to be taken.

Drift on 6 April 2006 :

The passage seems empty, cold, white and slippery. I want to hurry on and get out of this place quickly. I walk faster. I keep looking towards the horizon. Then I slow down, realising that if I walk faster my heels ring on the ground and the sound causes reverberation.

At the tram stop, routes cross, with pedestrians hanging around at the stop, others getting on or off trams, pedestrians coming and going between the two nearby squares, or walking along the street on the left-hand pavement. All these pedestrians have one thing in common, they are walking quite fast, giving the impression they are only passing through, that they did not come here for a stroll but because they have a specific purpose.

In this type of sensory configuration, flight or crossing are habitual styles of walk. Flight reflects the pedestrian's feeling of unease or insecurity. It differs from urban glide in the action and emotion it prompts. Flight is also characterized, not so much by speed as by a hurrying step. Pedestrians suddenly start walking faster as if they wanted to leave the place as soon as possible. In their precipitation and unease, they draw themselves inwards: gestures become jerky, arms are wrapped tightly round a handbag or jacket, the bust and face turn downwards. In such circumstances there is little chance of meeting or exchange. In crossing we are more likely to observe the tactics of negotiation and avoidance deployed by pedestrians to cope with urban furniture and other members of the public. Much as stamping this is a jerky, uneven style of walk. Crossing varies between waiting, hesitation and precipitation. Less active when waiting, a pedestrian's bodily and visual mobilization increases in moments of hesitation, becoming even more noticeable with precipitation. This type of walk is an illustration of how motion can be "shaped" by urban atmosphere.

Conflict is probably usual in the relations between pedestrians and urban atmospheres. It not only reflects the contradictions between pedestrians' expectations, the way they use a space and the city's sensory qualities, but also translates the everyday confrontation that opposes them. This opposition between pedestrians and the city feeds on the mobilizing quality of urban atmospheres. This mobilizing force sometimes determines a route and the pace of movement, but it can in some instances place a straitjacket on mind and body. This happens in places with a lot of people and a metabolic sound atmosphere. In a context of this sort pedestrians feel hampered or "gripped" by the atmosphere to such an extent that they may lose a degree of autonomy in their movement.

Drift on 20 April 2006

Pedestrian versus amenities. Here I encounter an example of particularly complex urban design which, to my mind, encapsulates the difficulties I have as a pedestrian in Grenoble: tram lines, lanes for motor traffic -with raised tram-stops and pavements, and in some cases no real pavement, just stubby posts, bollards or fencing separating the pedestrian area from motor traffic. Here the marks on the ground indicating cycle lanes (one in the road, one on the pavement, as I realise after thinking there are really too many cyclists here) and the pedestrian crossings, make walking very complicated.

Crossing is just as challenging, involving several stages. Sound plays an important part here: the passing of cars and trams is sufficiently audible in the overall calm to awake one's attention.

This conflicting relationship with urban atmospheres is embodied in a characteristic type of walk: stamping. This is a slow, jerky, sometimes impatient walk, particularly common when pedestrians want to continue on their way, but are forced to stay put or only advance with small steps, in keeping with the rhythm of the place or other pedestrians preceding them. In this type of walk the body is constantly mobilized: the bust leans left and right to avoid collisions and/or anticipate the next opening; the gaze focuses on other walkers or further ahead, while deliberately not staring at pedestrians coming the other way; lastly the feet grip the ground, sometimes even striking it. For this type of walk, the speed is substantially lower, the feet sliding cautiously over the ground. The feet are not raised, from the heel to the toe, but remain parallel to the ground, barely lifted. Steps are very short, the feet "sliding" forwards with a scraping, dragging noise. They progress at a snail's pace, but it does avoid complete immobility (after [START_REF] Morris | La clé des gestes[END_REF]. More than any other type of walk, stamping reveals the friction that constitutes urban existence and the almost tactile roots pedestrians put down in the city.

Conclusion

In other words, individual neighbourhoods, places and atmospheres all shape our way of walking, which is every bit as much a type of urban travel as a form of bodily expression [START_REF] Breton | Marche urbaine, Editions Métaillé[END_REF]. Alternatively we may say that walking in town is a carnal experience: "streets, pavements or pedestrian precincts are places where bodies avoid or approach one another, embrace, totter, hesitate, turn away, bend and settle into the city matter with a very special sensuality" (Thomas, 2007). In this process of constant exchange, walking and urban atmospheres are articulated with an almost plastic flexibility. Conflict, paradox, induction or even pleasure are, much as complicity and adjustment, types of relation between walking and urban atmospheres that evoke the intersensory dimension of the urban experience. As they walk pedestrians are constantly stimulated, inhibited, mobilized, carried away … by sounds, smells, colours and multiple flows. In these heterogonous configurations, crossing, flight or even strolling are every bit as much ways of embodying this sensory material as of taking bodily shape through the material.

The lexicons we propose here are just sketches, neither exhaustive nor closed on themselves. Other types of walk and other sensory configurations probably exist, expressing other types of relationship between walking and urban atmosphere. But these lexicons do give some indication of the complexity of the choices facing pedestrians and the ambivalence of walking processes [START_REF] Solnit | L'art de marcher[END_REF]. The walkability of a place or neighbourhood is probably due to its material design, but what makes a pedestrian walk is also the quality of a town to offer alternatives, awake the body and senses, stimulate emotion and exchange … ultimately modelling multiple forms of spatiality in movement. Such results raise questions about the Scandinavian norms, exemplified by the Stroget pedestrian precinct in Copenhagen, which are becoming widespread in Europe. Streets are intended to channel crowds, but the organization of traffic and the functionality of walking should also remain a collective concern [START_REF] Benjamin | Paris, capitale du XIXe siècle : Le livre des passages (Translated from German by Jean Lacoste)[END_REF], remaining a de facto means of urban expression. But, in the face of attempts to smooth the rough edges of city life, work on atmospheres -by giving meaning to the senses [START_REF] Straus | Du sens des sens. Contribution à l'étude des fondements de la psychologie (Translated from German by Georges Thinès[END_REF]) -offers a way of questioning street design in terms of sensory affordances for walking. This is a new perspective which, we believe, may open the way to a renewal of the ways we conceptualize city walking and urban design.

  Back with other pedestrians, I allow myself to be caught up in the movement (dynamic) of Cours Berriat. This attraction coincides with the impression of returning to a neighbourhood, in the sense that its population is visible, with activity and a sense of presence. All along the street there are neighbourhood shops, shoppers, clutter on the pavement: shop displays, advertising signs and so on. The pedestrians on this route display bodily movements expressing avoidance and contortion, sometimes stopping to allow the person coming the other way to pass. People's movement or simply their presence prompts me look into the side streets (Rue du Drac, Rue d'Alembert).I reach Cours Berriat and here it is much more lively, with more light, people getting into their cars and driving off. The Fontaine end of Cours Berriat is less attractive, not very brightly lit, whereas on the other side it leads to the town centre. Several youths are withdrawing cash outside the bank. A young woman cycles past on the tramline. There are one or two other people also cycling. I decide to cross the road. On the other side there is a kebab joint and a sandwich bar, with several people inside. I notice various meeting places, each with a few people. It is more conventional here, in the sense that there are bright, multicoloured lights, and traffic lights. Earlier on it was a feeling of solitude, really very quiet, giving the impression that one is no longer in the lively part of town, a neighbourhood with history, people, things going on and bright lights.

their appointed lane) but comprising several forms of traffic (trams, pedestrians, cars, cyclists). Impression of being carried away visually and bodily by this flow. At the St Bruno tram stop the impression of fluidity is broken. From here on everyone is constantly re-negotiating the trajectory and pace of forward movement..

	a given place and		walking)
	pace, avoiding		-Quiet, unhurried activity,
	contact).			loitering. Valid day and
	-	Pleasure		night
	accompanying		-Social throb of the
	walking.			street, at the St Bruno
				tram stop, with large
				numbers of pedestrians
				arriving and departing
			Example : Drift down Cours Berriat (Grenoble)
	QUALIFICATION	REFERENCE TEXT	ELEMENTS BROUGHT
	OF WALKING	PHOTO ILLUSTRATION	INTO PLAY BY
				WALKING
	SHOP FRONT STROLL (Along the Cours)	Fluid traffic on Cours Berriat. Long, wide thoroughfare, stretching into the distance, pulling a well-ordered flow (everyone has Buildings -Long, wide thoroughfare -Homogeneous, low-rise buildings
	-Stroll, without
	hurrying, but		Senses
	marked by		-Framed vista but
	pedestrian		opening onto distant
	vigilance, the		prospects.
	need constantly to		-Coloured lights at night
	avoid bumping		-Sound trail: tram
	into or rubbing		-Emergence: tram bell
	against the bodies		-Rhythmic sound and
	of others			vision
	-Being carried		-Metabolic: steps and
	away by the		voices at the St Bruno
	sights and		stop
	physical feelings.		-The street has a certain
	Sense of being		beat
	drawn despite
	oneself by the		Social
	street and		-Organized flow of people
	pedestrian flow		on the move, with various
	(required by other		means of locomotion
	bodies to walk at		(trams, bikes, cars,

  Drift on 7 April 2006A parenthesis in urban life. The riverside is split, at this time of day, into two climatic strips: one part in the sun; the other in the shade (on the built side). I opt to walk in the sun. I am cut off from the noise of road traffic, now barely audible far behind me as a background hum. Birdsong is predominant, wrapping me in a sound bubble. I walk slowly.

	Drift on 17 April 2006
	Here we enter a square. It has little walls on which one can sit. It is nevertheless quite large and
	spacious. A youth is practising tricks on a skateboard. Two other people are roller-blading. That
	makes quite a lot of people on rollers, but there are also one or pedestrians. It is about 21.00, on
	the holiday Monday of a long weekend.

Research was coordinated by Yves Winkin, Deputy-Head of the Ecole Normale Supérieure Lettres et Sciences Humaines in Lyon. The results presented here are taken from the work done by the Cresson team : Thibaud Jean-Paul (ed.), Bonnet Aurore, Leroux Martine, Thomas Rachel (2007). "Les compositions de la marche en ville", Contribution by the Cresson team to the final report, Winkin Yves and Lavadinho Sonia (ed.), Des villes qui marchent, tendances durables en urbanisme, mobilité et santé, Projet ANR SEST 05 019, Final report, Université de Lyon, ENS-LSH, 113 p. ; Intermediate report, Cresson, volume 1, January

2008, 105 p.2 This article reports on the work of the Cresson team as a whole, but the two results refer more specifically to analysis by Rachel Thomas concerning the establishment of exploratory registers for "types of walk", "walking describers" and "walking situations".3 For a detailed presentation of this methodological protocol, see: Thibaud, Jean-Paul (2008). Je-tu-il, la marche aux trois personnes in Urbanisme, n° 359,

In Geneva the Equiterre team deployed these survey protocols, assisted by the Cresson team, in the Cressy and Le Pommier districts.

All the photographs in this document, and all the commentaries on the various districts under study, are taken from the "Je" campaign. They were all taken, or made, by Aurore Bonnet, Martine Leroux, Jean-Paul Thibaud and Rachel Thomas.

This contribution contains the results of research funded by France's National Research Agency (ANR) on walking in towns. Research focussed on two cities: Geneva (Switzerland) and Grenoble (France).


Dr Rachel Thomas
email: rachel.thomas@grenoble.archi.fr

Dr Rachel Thomas Cresson

The power exerted by urban atmosphere over our choice of walk

It brought together sociologists, architects and town planners around the question of the prerequisites for city-dwellers to decide to walk in town? Four districts, two in Grenoble (France) and two in Geneva (Switzerland), served as a basis for field work in three phases: surveys combining an architectural and sensory approach to the terrain; interviews with users; and ethnographic observations of walking practice. The results of the research throw doubt on the spatialist approach, still influential in architecture, which maintains that space determines usage. The findings suggest the need for a reappraisal of the power exerted by atmosphere over walking and urban practices. Atmosphere, by influencing both registers of walking (doing and experiencing), demonstrably contributes to the walkability of a place, just as much as its design does.

BRIEF BIOGRAPHY OF Dr. Rachel THOMAS

Sociologist, researcher to CNRS, she works about accessibility and mobility of pedestrian in urban public space. Her research raises two questions : which is the role of perception and atmosphere in the practices of walk ? which methodologies develop to analyse bonds between perception, walk, atmosphere and urban environment ?

Introduction

What are the pre-requisites for a city-dweller to decide to walk in town? Is the quality of urban design sufficient to encourage city walkers? These two questions were the focus of a Franco-Swiss research action funded by the National Research Agency (ANR) between 2005 et 20071 . Teams of sociologists, architects and town planners observed the real walking practice of pedestrians in Grenoble and Geneva. They then analysed the modes of action and the type of relationship to the urban environment implied by such practice. In other words the aim was not to watch walking from a distance but on the contrary to address it in situ, in its concretism. Work was guided by two assumptions. The first, theoretical assumption, questioned the commonly held idea that walking is a uniform, generic activity. On the contrary there are different ways of walking in town depending on the practical and sensory context. The second, methodological assumption, emphasized the need to reconcile the purpose of research and the approach adopted in the field. This meant that to address walking practice we too should get walking.

Field proceedings

To this end an innovative methodological protocol was tested in four districts -two in Grenoble (France) and two in Geneva (Switzerland) -the three-person walk2 . By dividing the survey into three phases we were able not only to address the ordinary pedestrian experience in an urban environment but also to share its various dimensions -practical (walking savvy), social (being together) and affective (walker perceptions and feelings).

In the first-person ("I-walk"), the researcher is immersed in the study zones taking photographs at whim for half a day. He or she walks freely, without previously defining a route, drawn onwards by the terrain and atmosphere. A dictaphone is used to record passing impressions, in conjunction with a digital camera to fix noteworthy events, situations or vistas. Once this non-directional walk is complete the researcher produces a summary document in which the narrative and photographs bear witness to the route as it was perceived.

Drift down Cours Berriat (Grenoble)

In the second-person ("you-walk"), the researcher carries out a series of pavement interviews with pedestrians. Accompanying them on a portion of their journey he or she questions them on the reasons for their journey, the choice of route and how they see the neighbourhood. A dictaphone is used to record their answers as they walk. The recording helps to plot the routes taken on a map and serves as the basis for a transcription of the answers given pedestrians.

Lastly, with the third-person ("he or she-walk"), the researcher carries out "route reproductions". He or she follows unidentified pedestrians at a distance, paying attention to their practical actions (how they cope with the developed space) and social conduct (how they handle encounters, the presence of others or a crowd). This sort of tailing, also recorded on a dictaphone, is transcribed in two ways: plotting on the map of the observed route; and a written description (gestures, trajectory, speed of movement, events, etc.) recorded in situ.

This survey protocol was experimented in two districts of Grenoble -Ile Verte and Europole -and two others in Geneva -Pommier and Cressy. In Grenoble, which will be the focus of the present paper, we chose the neighbourhoods to be studied for several reasons: powerful identity close to the city centre, direct access to the centre on foot or by public transport, extreme heterogeneity of the urban contexts on offer for walking. Whereas Ile Verte offers its inhabitants a large number of parks and residential areas where they may stroll, the new Europole business district confronts pedestrians with more recent developments, in which the minerality and transparency of glass surfaces offers a uniform setting for walking.

The minerality of the Europole district

The landscaped setting of the Ile Verte neighbourhood However the walkability of these districts should not only be judged by their landscaped or commercial attractiveness. On the contrary, walking is the result of a complex combination of conditions determined by practical possibilities, the pedestrian's own wishes and the ability of the environment to stimulate perception.

The sensory configurations of walking

More exactly architectural and urban atmospheres contribute just as much to the choice of walking as the quality of urban design available to the pedestrian. The analysis carried out as part of this research action shows that some sensory configurations are more conducive to travel by foot than others. By "sensory configuration" we refer to the result of the process by which pedestrians select, organize then shape the sensory material structuring their perception and action during the journey [START_REF] Thomas | Les trajectoires de l'accessibilité. Grenoble : A la Croisée[END_REF]. Six sensory configurations were identified: attractive, spreading out, mobilizing, suspensive, accelerating and inhibitive. Each one operates jointly or separately on motor action and at an affective level.

For example, the attractive mode encourages exercise through walking and triggers pleasure in the pedestrian. This sensory configuration is characterized by powerful, rhythmic sound, numerous visual openings and lively sociability. The combination of these characteristics not only contributes to setting a tempo for walking but also awakens the subject's senses. Caught up in and carried away by the atmosphere pedestrians adjust their gait to the pace of the place, listening to their surroundings and extending their visual attention. Bodily and perceptive immersion prompts a state of harmony that procures a feeling of pleasure and well-being. Strolling or ambling embody this pleasant relationship. Walking in this way, pedestrians are open to others and to outside events. This "particular form of walk imply obviously any desire to arrive some share. Walk is an end in itself. (…) it frequently implies breaks to look at or converse ; it is often combined with physical contacts between the companions of walk" (Morris, 1978).

The pleasurable feeling is also prompted by the suspensive configuration, but unlike the previous one it replaces walking with loitering or longer stays. In other words the suspensive configuration suddenly breaks the pace of progress, raising the pedestrian's perceptive acuity and reducing contacts with others: under the influence of crystal-clear or reverberating sound atmospheres, rough or slippery surfaces, a landscaped or stylized backdrop, the pedestrian stops walking and adopts a contemplative pose. In this case, the aim is to take the time to enjoy the environment's remarkable qualities.

However the quality of the urban environment is not always sufficient to encourage citydwellers to go by foot. The inhibitive mode is a perfect illustration of this assumption. Such places offer pedestrians ideal conditions for walking -wide, unencumbered pavements, smooth surfaces, agreeable night-time lighting, visual directionality, etc -but paradoxically they also make walking somehow inadequate. More exactly, although this type of environment facilitates walking it nevertheless makes the pedestrian feel ill at ease and out of place. Faced with an anti-septic environment the pedestrian feels foreign and, at the same time, exposed to the glances of local inhabitants. Moving through this vacuum, walking turns into flight, a brief crossing or a form of infiltration. In the first case the pedestrian suddenly starts to hurry. In the anguish of this precipitation their body shrinks in on itself, gestures become jerky, the torso and face turn downwards, bowed over in self-protection. In the two other cases the style of walking betrays a functional relationship with the surroundings. Crossing involves taking advantage of design features that facilitate faster progress and a more streamlined gait. Infiltration is a slower, more cautious way of walking, the aim being to enter a place discreetly while keeping watch for visual and sound events that may reveal another's presence.

For each of these sensory configurations the architectural and urban atmospheres consequently exert an influence on the two registers of walking, doing and experiencing. By providing pedestrians with a sensory basis for their conduct and awakening in them a range of emotions, they contribute just as much to walking as does urban design. Furthermore they prompt ways of relating to the city that are probably related to our daily choice of a means of locomotion.

Heterogeneous walking situations

In other words, architectural and urban atmospheres also play a part in the intensity of the relationship between the pedestrian and the city. We may distinguish walking situations that reflect such relationships: paradox, opposition, adjustment, neutrality and conniving. These situations are neither predefined nor stable during an urban journey. They evolve, succeed or confront one another depending on objective material conditions, fuzzy, fluctuating sensory conditions, and the affective state of the pedestrian.

Paradox thus reflects an ambiguous relationship, a disparity between the (physical and sensory) contexts of walking and the pedestrian's (perceptive and emotional) expectations. This situation is observed in two specific cases. Firstly the quality of urban design fails to make up for the poverty and the unappealing atmosphere. Walking is chosen and the location traversed for strictly functional, practical reasons: doing shopping, going to a meeting or to work. In this type of context, walking does not become a set habit and another form of locomotion, less in keeping with the environment, may take its place: Immersion on 6 April 2006: I "enter" the avenue walking along the left-hand pavement. The pavement is wide and comfortable, easy on pedestrians. Ahead the Chartreuse range rises, but it is not at all overwhelming, more a goal to achieve on which my gaze is concentrated. Perhaps too because nothing much in my immediate surroundings is really captivating. The avenue is deserted and I am walking into the wind, which is unpleasant. The facades of the building that line the avenue are very forceful in the landscape, a constraint on the way I walk and where I look. I am not ill at ease, just bored, looking for a way out.

In the other case the quality of the atmosphere makes up for the shortcomings of the design and makes the place genuinely attractive. With the prospect of various routes, a pulsating sound atmosphere, an open visual field that excites the senses, instils a feeling of freedom and well-being, and contributes to the overall good mood. Pedestrians really settle into this environment, to such an extent that they frequently walk through here or turn a simple walk into a pleasant stroll:

Immersion on 20 April 2006: the thoroughfare is immediately attractive. There is a quiet bustle of activity on the shaded left-hand pavement: young people around a cash point, others sitting outside a café, passers-by, cyclists, trams. There are not many cars at this time of day. The contrast between sunlight and shade, that one cannot fail to notice, is both an invitation to take sides and an ingredient all the way along the route in some ephemeral spatiality. I am inclined to start by walking along the street, without hurrying, fitting in with the easy-going springtime mood, then perhaps to digress.

To conclude, the situation of neutrality is fairly close to what Richard Sennet describes in reference to contemporary towns. It reflects the fit between the conditions for walking due to urban design, the atmosphere of the place and the aims of the pedestrian. More specifically such situations are found in environments that reassure people that nothing disturbing nor demanding will happen outdoors. In the neighbourhoods we studied, this situation of neutrality may be observed in urban fabrics and various configurations, but they all share at least one feature: the capacity of the place to permit the practical realization of walking; the low ability of the atmosphere to "catch" the pedestrian's visual and sound attention.

In other words architectural and urban atmospheres modify the way we walk and shape the pedestrian's relationship with the city. In addition such atmospheres play just as large a part in the attraction, or repulsion, exerted by a place as the degree to which the pedestrian settles into the city. Awakening or neutralizing the senses and the body, giving places a strong identity, or dispelling it, architectural and urban atmospheres maintain an almost carnal relationship between the pedestrian and the city, which we may assume is largely decisive in the choice and style of walk.

Conclusion

These results prompt us not only to reconsider the power atmospheres exert on our daily urban practice but also to propose lines of thought for developers, taking atmospheres as our starting point.

Architectural and urban atmospheres are not neutral for the pedestrian. Along an urban route they operate as resources or hindrances for walking. More than just a medium for motive action they operate as sensory levers and as forces creating affection. By awakening the senses, proposing alternatives to the rigidity of the material space, punctuating urban travel time with noteworthy events, atmospheres give substance to walking and enable multiple modes of action and affection to express themselves. Seen from this point of view proposing quality spaces for walking means thinking of pedestrian areas primarily as a carnal space, and only then as a space for movement : "streets, pavements or pedestrian precincts are places where bodies avoid or approach one another, embrace, totter, hesitate, turn away, bend and settle into the city matter with a very special sensuality" [START_REF] Thomas | La marche en ville. Une histoire de sens[END_REF]. It is the

Fluid

  traffic on Cours Berriat. Long, wide thoroughfare, stretching into the distance, pulling a well-ordered flow (everyone has their appointed lane) but comprising several forms of traffic (trams, pedestrians, cars, cyclists). Impression of being carried away visually and bodily by this flow. At the St Bruno tram stop the impression of fluidity is broken. From here on everyone is constantly renegotiating the trajectory and pace of forward movement.. Buildings -Long, wide thoroughfare -Homogeneous, low-rise buildings Senses -Framed vista but opening onto distant prospects. -Coloured lights at night -Sound trail: tram -Emergence: tram bell -Rhythmic sound and vision -Metabolic: steps and voices at the St Bruno stop -The street has a certain beat Social -Organized flow of people on the move, with various means of locomotion (trams, bikes, cars, walking) -Quiet, unhurried activity, loitering. Valid day and night -Social throb of the street, at the St Bruno tram stop, with large numbers of pedestrians arriving and departing

Research was coordinated by Yves Winkin, Deputy-Head of the Ecole Normale Supérieure Lettres et Sciences Humaines in Lyon. The results presented here are taken from the work done by the Cresson team: Thibaud Jean-Paul (ed.), Bonnet Aurore, Leroux Martine, Thomas Rachel (2007). Les compositions de la marche en ville. Grenoble : Rapport Intermédiaire Cresson, volume 1, January, 105 p.

 2 Thibaud, Jean-Paul. "Je-tu-il, la marche aux trois personnes", Urbanisme,

n° 359, 2008, March-April, pp. 63-65.

Research presented here was financed by the National Research Agency (ANR) between 2005 and 2007.