What is air pollution?
Air pollution refers to a mixture of gases and airborne particles present in the air (indoors or outdoors), whose concentration levels vary depending on emissions and weather conditions, and which are harmful to health and the environment.
The 1996 Air Quality Act provides the following definition: "Air pollution consists of […] the introduction by humans, directly or indirectly, into the atmosphere and enclosed spaces, of substances having harmful effects such as endangering human health, harming biological resources and ecosystems, influencing climate change, damaging property, or causing excessive odor nuisances."
Sources of outdoor air pollution are diverse
Some of them are natural: pollen, desert dust, and dust and gases emitted by volcanoes during eruptions, in particular.
Others, known as anthropogenic, result from human activity. Anthropogenic pollutants can be:
primary: directly emitted from pollution sources (road traffic, industry, heating, agriculture, etc.). These include, for example, nitrogen oxides (NOx), sulfur dioxide (SO2), volatile organic compounds (VOCs), hydrocarbons, and certain metals (lead, cadmium, etc.);
or secondary: created in the atmosphere through chemical reactions between pollutants. These include ozone, nitrogen dioxide, and ultrafine particles…
Particulate matter suspended in the air (PM10 and PM2.5) constitutes a generic category that includes both primary and secondary particles.
|
Pollutant |
Symbol or abbreviation |
Sources |
|---|---|---|
|
Volatile organic compounds (benzene, etc.) |
VOC |
Found in indoor air or urban environments due to wood burning, vehicle exhaust, the use of solvents, etc. |
|
Nitrogen dioxide |
NO2 |
Road transport, thermal power plants, heating systems, incineration plants, gas stoves, etc. |
|
Sulfur dioxide |
SO2 |
Thermal power plants, heating systems, large industrial facilities, refining and smelting operations |
|
Heavy metals (cadmium, mercury…) |
- |
Waste incineration, steel production, combustion of fossil fuels |
|
Carbon monoxide |
CO |
Industrial activities, fuel combustion, metallurgy |
|
Ozone |
O3 |
Formed primarily in urban areas, upon contact with certain pollutants and under the influence of heat and UV rays or laser beams, high-voltage electricity, or electrostatic discharges |
|
Fine particles (<2.5 µm) |
PM2.5 |
Industrial combustion, heating systems, incinerators, engines, volcanic eruptions, sandstorms |
|
Fine particles (<10 µm) |
PM10 |
These pollutants can also be found in indoor environments (homes, workplaces, public spaces, etc.). There are also numerous sources of pollution in these settings: cooking, smoking, mold, building materials, furniture, dust mites, cleaning products, paint, pet dander, and more. This is what is known as indoor air pollution. We are also highly exposed to it due to our current lifestyle; the majority of the general population spends about 80% of their time in these increasingly confined indoor spaces.
In relation to
Climate change
thematic dossier
Climate change is rapidly and profoundly altering the environment. The health impacts of climate change are numerous and varied.
Asthma
thematic dossier
Asthma is a chronic respiratory disease characterized by attacks, which are episodes of breathing difficulties (dyspnea). Asthma has a significant impact on patients’ quality of life.
thematic dossier
Cardiovascular disease and stroke
Les maladies cardio-neuro-vasculaires regroupent un ensemble de troubles affectant le cœur et les vaisseaux sanguins.
