The village of Champlan in Essonne was selected as a pilot site to study the exposure of suburban populations to various major infrastructure projects (Orly Airport, expressways and highways, waste incinerators, high-voltage power lines, etc.). A scientific committee composed of agencies responsible for the environment and environmental health was formed. The InVS, which was asked to launch an epidemiological study, wished to precede its decision with a sociological study focusing on the health concerns of the population. This study comprised two components: the first aimed to analyze the political, institutional, and social context to understand the emergence of the mobilization as well as how it was addressed. The second component focused on characterizing the health concerns of the various population groups living in Champlan. The data for the entire study were collected from approximately sixty confidential, semi-structured interviews, supplemented by documents produced by the stakeholders or operators of the facilities in question. We might ask why the social demand emerged in this municipality and not in neighboring municipalities that are only slightly less exposed. We also wanted to examine the nature of the link between exposure to nuisances and health concerns. Champlan is a village that offers not only a certain quality of life but also relatively close interpersonal ties. These characteristics attract residents who are willing to accept the noise from Orly’s aircraft because the lower property values offer them a village lifestyle (house, garden, social ties, various amenities) close to Paris. This initial trade-off (which varies depending on when residents moved in, their exposure to varying levels of infrastructure, and the local connections they have forged) constitutes a shared norm among residents and is integral to their distinct identity. It provides a benchmark for the effort each family is willing to make in the face of potential environmental degradation. Any increase in inconvenience or a new source of nuisance requires an additional effort, which depends on individuals’ resources. Economic, family, and health crises (chronic, disabling, child-related, or irreversible illnesses) are, in this regard, key factors explaining the intensity of complaints or involvement in active mobilization due to the upheaval they cause. Conversely, the intensity of expressed health concerns appears to be only slightly, if at all, linked to the number of exposures experienced. Paradoxically, health concerns are voiced in Champlan rather than in neighboring municipalities because its residents have the resources to build and sustain their complaints. The presence of a national-level politician focused on environmental issues helps bring the village’s specific situation to the public stage. The existence of easements constitutes a shared experience that unites residents, at the very least, around common concerns. However, health concerns remain limited to those who feel threatened by a series of disruptions, who directly or indirectly suffer from chronic, serious, or disabling conditions, or who are anxious about situations of uncertainty (high-voltage power lines) that risk undermining the validity of their choice to live in Champlan. (R.A.)