Fine particle pollution caused 307,000 premature deaths in the European Union in 2019, according to a report by the European Environment Agency. An alarming figure, but decreasing by more than 10% in one year, thanks in particular to favorable weather conditions. Fine particle air pollution is responsible for 40,000 deaths each year in France. Much remains to be done concerning air quality.
When pollution exceeds alert levels, it's a pollution peak. What is it really? How does it appear and is it measured? By who and what are the consequences on our health? How can we protect ourselves against pollution peaks?
When air is said to be polluted?
Air is said to be polluted when a certain quantity of fine particles per cubic metre of air is exceeded. The European Parliament has set thresholds for the concentration of pollutants beyond which there is a risk for populations.
For those who like numbers, here are some:
The new recommended 24h thresholds are lowered from 25 to 15 µg/m3, for PM 2.5, and from 50 to 45 µg/m3 for PM10. The maximum average concentration recommended over a year is reduced from 10 to 5 µg/m3 for PM2.5, and from 50 to 45 µg/m3 for PM10.
What causes a pollution peak?
It depends on the pollutant in question, but generally pollution peaks are due to emissions of pollutants from human activity (transport, industry, agriculture, burning of waste) and natural sources (pollen, volcanoes, landfires, etc.), associated with weather conditions that are not conducive to good air quality:
- The lack of wind is problematic because it disperses pollution.
- Humidity, heat or solar radiation promote the chemical transformation of pollutants and the production of secondary pollutants.
- Ozone pollution episodes occur mainly in summer, on hot, sunny days.
- In periods of extreme cold, with anticyclonic conditions, it happens that the layer of air on the ground is colder than the upper layers: this phenomenon is called " thermal inversion " This limits vertical air movements and pollutants are blocked on the ground without the possibility of dispersion.
According to CITEPA (Interprofessional Technical Center for the Study of Atmospheric Pollution) in 2019 (for the year 2017):
- Around 90% of primary particulate matter and nitrogen oxide emissions from road traffic come from diesel vehicles.
- 75% of sulfur dioxide emissions are linked to industry,
- 85% of fine particle emissions from the residential sector are due to heating, 70% of ammonia is linked to agriculture.
How to know the level of air pollution?
A pollution peak occurs when a threshold is reached beyond which short-term exposure poses a risk to the human health of sensitive individuals. If particle and ozone pollution persists for more than 3 days, the authorities must implement measures under the alert procedure.
The Atmo index (which ranges from 1 to 10) allows you to know by color code the level of air pollution observed.
- From 1 to 4: air quality from very good to good
- 5 to 7: average to poor quality
- From 8 to 10: poor or very poor quality
It represents the concentration of 4 pollutants: 10µm particles (PM10), sulfur dioxide (SO²), nitrogen dioxide (Nox) and ozone (O3).
There are many applications monitoring air quality in real time almost anywhere in the world (at least where there are sensors).
Who measures the level of air pollution?
In France, there are 13 Approved Air Quality Monitoring Associations (AASQA) that operate 650 fixed air analysis stations spread throughout the country. They are approved by the Ministry of Ecology to communicate their information to the public.
Are we more exposed in a car or on a bike?
Motorists, located in the heart of traffic, are more exposed than people walking or bicycling. Indeed, the air entering inside a car is particularly polluted and tends to accumulate there. The concentration of nitrogen dioxide can even be 4 to 5 times higher in a vehicle driving on the Paris ring, than downtown. It's up to 15 times for a car driving in a jammed tunnel!
According to studies conducted in France and abroad, the levels of pollutants to which cyclists are exposed are almost a third lower than for car passengers, on the same road. Cyclists are freer to choose their place on the road and they have the possibility of using certain facilities such as cycle paths that slightly distance them from the flow of traffic. Even if the cyclist inhales more air due to his physical effort, the benefits of cycling are largely positive for health.
Who are the most exposed people during a pollution peak?
Children, pregnant women, the elderly, people with asthma or suffering from cardiovascular or respiratory diseases are most at risk of seeing a symptom worsen or an illness develop.
In the event of a particle pollution episode (PM10), nitrogen dioxide (NO2) and sulfur dioxide (SO2): sensitive and vulnerable people should favor moderate-intensity sports activities. The population should reduce or even postpone intense sporting activities.
In the event of an episode of ozone pollution : sensitive and vulnerable people should avoid intense sporting activities (including competitions) outdoors; they can maintain these activities indoors; the general population can maintain intense sporting activities indoors.
Is it effective to wear a facemask during a pollution peak?
Only the largest airborn particles are stopped by the scarves placed over the nose and mouth or the paper masks (surgical masks). However, it is not the largest particles that are the most dangerous for health, but the finest. Wearing this type of protection is therefore useless because it does not stop the fine particles that enter our respiratory system and are the source of pathologies. Most anti-pollution masks are designed to protect against particles but do not protect against gaseous pollutants. Their effectiveness depends in particular on the correct fit to the face, their maintenance and the presence of a minimum FFP2/N95 standard.
It will therefore be necessary to buy masks with different sizes to adapt to the shape of the face and to have the best possible airtightness (the maximum amount of air inhaled passes through the filters rather than on the sides or along the nose), washable masks with interchangeable filters. Frogmask anti-pollution masks perfectly meet these 3 essential criteria.
