Air emission quantification methods

The Environmental Code grants everyone the right to breathe air that is not harmful to their health, i.e. air in which concentrations of substances that may be harmful to human health and other ecosystems do not exceed reference levels defined for this purpose.

Air quality is monitored via networks that measure concentrations of the substances concerned: SO ₂ , NO ₂ , CO, O ₃ , VOCs (volatile organic compounds), lead... These networks, managed by approved air quality monitoring associations (AASQA), are mainly located in population exposure zones (conurbations, industrial zones...). They are made up of fixed sensors and laboratory trucks, supplemented by modeling tools to cover the entire geographical area concerned. AASQAs are mainly concerned with substances covered by European directives on air pollution. In recent years, the issue of health impact has become increasingly important, and actions are beginning to take shape (cf. Plan National Santé Environnement). As a result, the number of substances or compounds to be addressed is increasing.

Air concentration levels are indicators of the "state" of the environment. They depend on the extent of atmospheric emissions linked to human activities (heating, transport, etc.) and natural phenomena (volcanism, etc.), which are indicators of "pressure" on the environment.

The relationship between "pressure" (emissions into the atmosphere) and "state" (air quality) is complex to establish. This is because, on the one hand, the substances emitted are transported at varying distances from the source and, on the other, undergo multiple physico-chemical transformations, particularly under the action of solar radiation.

As part of their environmental policy, public authorities are encouraging the development of models to represent these phenomena and to establish the occurrence of pollution episodes and the impact on health, in order to take precautionary measures in the short term and guidelines...