Locally, controversies concerning air quality measurements are frequent and a major explanation is the large discrepancies between perceptions and quantitative measurements. These controversies show the importance of social and health issues linked to this question and the fact that air pollution often implies a "perceptual ambiguity". In this paper, we discuss the place of knowledge in the mechanisms of perception of air quality. In this perspective, the French Approved Air Quality Surveillance Associations (AASQA), face a major challenge: translating complex scientific knowledge into comprehensive and appropriable information that sometimes contradicts sensory perceptions. Atmo Auvergne-Rhône-Alpes (AASQA) has developed a mobile application, Air To Go, that provides data describing air quality with high geographical accuracy (10 meters) and we are investigating in how access to very precise information might modify the individual perception of air pollution. The results show that there is a need to characterise the influence of the perceptual filter on the in the way individuals view air quality, both to improve the perception of risks and to change individual behavior in terms of exposure and emission of pollutants.