The air we breathe is made up of 99% oxygen and nitrogen but also of natural and human-induced pollutants, that may have a short or long-term impact on our health. Get an insight into the main air pollutants!

1. Nitrogen dioxide (NO2)

• What is it? It is a suffocating and irritating gas that can be easily recognized thanks to its red-brown color. It also has a pungent odor.
• Where does it come from? Mainly from combustion (heating, electricity generation, vehicle and boats engines). 50% of NO2 emissions are due to traffic.
• What are the risks? NO2 is responsible for bronchitis and asthma, especially for children. A high concentration of NO2 may also contribute to the decrease of the lung function.

2. Particulate Matter

• What is it ? These are small solid particles that can penetrate in the airways and lungs. The finest ones can even bind to blood vessels. PM10 (PM standing for particulate matter) refers to particles smaller than 10 microns in diameter and PM2.5 for those smaller than 2.5 microns.
• Where do they come from? Human activities such as road traffic or energy transformation and from natural phenomenons such as volcanic eruptions. The PM concentration in the air significantly varies according to temperature and wind speed. They are particularly prevalent in cases of extreme cold and lack of wind, which prevents the particles to disperse.
• What are the risks? Fine particles cause many nasal allergies. Chronic exposure to fine particles is a risk factor for cardiovascular and respiratory diseases as well as lung cancer.

3. Ozone (O3)

• What is it? Ozone is a major component of smog. The pollutant ozone found at ground level shouldn’t be confused with the ozone layer found in the upper atmosphere — the one that protects us from UV rays.
• Where does it come from? The concentration of ozone is particularly high when the sun shines intensely.
• What are the risks? Ozone might cause asthma, eyes irritation and can lead to respiratory and heart diseases.

4. Volatile Organic Compounds (VOCs)

• What is it? These are molecules made mainly of carbon and found as gases in the air we breathe. They are very volatile and spread far away from their places of emission.
• Where do they come from? VOCs are emitted by traffic, industries, the residential sector and also by vegetation. Indoors, important emitters of VOCs are cleaning and DIY products as well as some floor and wall coatings.
• What are the risks? In case of high concentration, they can cause irritations and a decrease of the breathing capacity. Some VOCs are classified as carcinogenic.

5. Sulfur dioxide (SO2)

• What is it? Sulfur dioxide is a colorless gas that smells like a burnt matchstick. Combined with oxygen and water, it is responsible for acid rains.
• Where does it come from? Mainly from power plants, smelters and refineries.
• What are the risks? It can irritate the skin and the respiratory tract. At high concentrations, it can even cause respiratory diseases and modify the lung defense mechanism.

6. Carbon monoxide (CO)

• What is it? It is a colorless, odorless and tasteless gas…therefore very difficult to detect.
• Where does it come from? Incomplete combustion heaters and vehicle exhaust gases.
• What are the risks? At high concentrations, carbon monoxide can cause poisoning characterized by headache, nausea and vomiting. Carbon monoxide is particularly present and dangerous indoor and can lead to coma and death in case of prolonged exposure.

…And to make it trickier, gross concentration of air pollutants changes all the time.

Add a little gust of wind or a ray of sunshine, a morning traffic jam, a residential heating peak… and air quality is turned upside-down in a matter of minutes, for better or for worse! Hence the importance of following its evolution closely. Obviously, you don’t have time to keep checking pollution indexes… but thanks to the Plume Air Report, our air quality forecast app, you can get real-time notifications and easily adapt your activities according to pollution. 🙂