1. Atmospheric environment and quality determinants

On average, an adult breathes 14 kg of air every day, while consuming around 1.5 kg of food and 2 kg of water. The atmosphere also plays a major role in regulating climate and maintaining the living conditions of the biosphere. However, air quality is by no means immutable in time and space, as its composition is the result of a complex balance between, on the one hand, the permanent input of matter from natural sources or human activities and, on the other, the continuous elimination and recycling of this matter through various physico-chemical mechanisms (dry and wet deposition of gases and particles, transformations in the atmosphere, assimilation by vegetation, oceans, etc.). If the balance of these exchanges is disrupted – particularly as a result of human activity –, the composition of the air is affected, with the risk of undesirable effects on health and the environment....