Air quality is probably one of the first health and environmental concerns of this new century. The media is talking about it more and more. And for good reason. We breathe about 15,000 liters per day. So there are many reasons to be concerned about what passes through our mouth and nose to go directly into our breathing machine, the lungs. The quality of the air, one could say that it is its level of cleanliness. To know it, you have to know what is going on in it. To know what is going on, there are people who observe, measure, model, inform and make decisions according to all this and the standards that have been decided.

From this page, we try to guide you step by step to know everything about air quality. This subject is certainly complex, but it is not complicated. When we founded Breathe, we started from scratch. But as we read, we began to understand. Click on the links you find and let us take you to the many pages of this site. Do you know a lot about air? Give us your feedback, and improve the content of our site. We are only simple citizens in self-training.

Air quality observation

If we schematize, there are on our beautiful planet several “compartments”. The earth, the water, and the air. As far as the air is concerned, it is a mixture of gases (nitrogen, oxygen, argon, carbon dioxide, etc.). Normally, we do not see it and we do not feel it. This mixture of gases that surrounds the earth is called the atmosphere. As we can see every day, the atmosphere is always different. Meteorology informs us about atmospheric phenomena, that is to say, their movements, humidity, pressure, and temperature. We understand, with all these parameters, the formation of clouds, rain, etc.

To understand the variations in air quality, it is important to understand the variations in the atmosphere. We can observe, even without a device, the changes in air quality. For example, the atmosphere can change color depending on the presence of certain gases, such as nitrogen dioxide. The opacity increases with the rate of fine particles in the air. The smell is more or less strong depending on the presence of aromas released during combustion, whether fuel oil, wood, or fuel.

The observation is completed by the measurement. Air quality metrology is an activity that mobilizes many actors in France, with increasingly sophisticated equipment.

Air quality measurement

Air pollutants are very numerous because they cover almost everything that human activities have created in the form of synthetic molecules, in their raw state, transformed or burned, in the form of gases or particles of matter. The air has nothing pure anymore, unfortunately. It contains a very complex mixture of all these pollutants, with concentrations varying according to the place where we are and the season. In France or abroad. In the country or in the city. In summer or in winter. Near the coast, in a basin, or at altitude. Near tertiary or industrial economic activities.

In France, those to whom the State has officially asked to measure air quality are the Associations Agréées de Surveillance de la Qualité de l’Air (AASQA). They are grouped in a network, ATMO, and are at the heart of the air quality monitoring system, which includes research laboratories around these measurement issues, such as Ineris, the Laboratoire National de Métrologie et d’Essais and Mines Douai. They send their data to the Centre Interprofessionnel Technique d’Etude de la Pollution Atmosphérique (CITEPA), which itself sends them to the Ministry of the Environment. Everything is centralized at the European level by the European Environment Agency which is linked here.

How is air quality measured? With measuring devices, often pollutant by pollutant. With technologies based on laser, chemiluminescence, flame ionization, and many others. These devices are placed on the territory, close to the traffic (proximity stations), far from the traffic (background stations), and close to industrial zones to be particularly monitored. These devices transmit the concentration data and each AASQA puts them online on their website, available to the general public. To make it simple, all these data are compiled on a scale of values from 0 to 100 and colored from blue to red, called ATMO Index.