Understanding pollution

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

Particulate Matter (PM10 and PM2.5)

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 from dispersing.

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.

Nitrogen dioxide (NO2)

What is it? NO2 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 boat 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 decreased lung function.

Volatile Organic Compounds (VOC)

What is it? These are molecules made mainly of carbon and found as gases in the air we breathe. They are very volatile and can spread a long way away from their emission source.

Where do they come from? VOCs are emitted by traffic, industries and the residential sector, and also by vegetation. Indoors, cleaning and DIY products are important emitters of VOCs, as well as some floor and wall coatings.

What are the risks? In cases of high concentration, they can cause irritation and decreased breathing capacity. Some VOCs are classified as carcinogenic.