WHAT IS A POLLUTION PEAK?
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 one that has decreased by more than 10% in a year, thanks in part to favourable weather conditions. Air pollution by fine particles is responsible for 48 000 deaths each year in France. So there is still a lot to be done.
When is the air said to be polluted?
Air is said to be polluted when a certain amount of particles per cubic metre of air is exceeded. The European Parliament has set thresholds for the concentration of pollutants above which there is a risk to people.
For those who like numbers, here are some of them:
The new recommended 24-hour thresholds are lowered from 25 to 15 µg/m3 for PM2.5 and from 50 to 45 µg/m3 for PM10. The maximum recommended one-year average concentration is lowered 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, waste burning) and natural sources (pollen emitted by plants, volcanoes, forest fires, etc.), combined with weather conditions that are not conducive to good air quality:
- The absence of wind is problematic because it disperses pollution.
- Humidity, heat or solar radiation favour the chemical transformation of pollutants and the production of secondary pollutants.
- Ozone pollution episodes occur mainly in summer, on hot and sunny days.
- In periods of very cold weather, with anticyclonic conditions, the air layer on the ground may be colder than the upper layers: this phenomenon is called "thermal inversion". This limits the vertical air movements and the pollutants are blocked on the ground without possibility of dispersion).
According to CITEPA (Centre interprofessionnel technique d'études de la pollution atmosphérique) 2019 (for the year 2017):
- About 90% of primary particulate matter and nitrogen oxide emissions from road traffic come from diesel vehicles.
- 75% of sulphur dioxide emissions are related to industry,
- 85% of fine particulate emissions from the residential sector are due to heating, 70% of ammoniac 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 human health for sensitive individuals. If particulate matter and ozone pollution persist for more than 3 days, the authorities must implement measures under the alert procedure.
The Atmo index (which ranges from 1 to 10) indicates the level of air pollution observed by means of a colour code.
- From 1 to 4: very good to good air quality
From 5 to 7: average to poor quality
From 8 to 10: poor or very poor quality
It represents the concentration of 4 pollutants: fine particles of 10µm (PM10), sulphur dioxide (SO²), nitrogen dioxide (Nox) and ozone (O3)
Numerous applications allow to follow the air quality in real time almost everywhere in the world (well where there are sensors)
Who measures the level of air pollution?
In France, there are 13 agreed associations for air quality control which operate 650 fixed air analysis stations throughout the country. They are approved by the Ministry of Ecology to communicate their information to the public.
Are we more exposed by car or by bike?
Car drivers, who are in the middle of traffic, are more exposed than pedestrians or bike commuters. Indeed, the air that enters the passenger compartment is particularly polluted and tends to accumulate there. In a vehicle travelling on the ring road, the concentration of nitrogen dioxide can even be 4 to 5 times higher than the ambient level in Paris downtown and up to 15 times higher for a car travelling through a congested tunnel!
According to various studies conducted in France and abroad, the levels of pollutants to which cyclists are exposed are almost a third lower than in the passenger compartment of a vehicle, on the same route. Cyclists have more freedom to choose their place on the road and can use certain facilities such as cycle lanes that take them slightly away from the traffic flow. Although cyclists inhale more air as a result of their physical effort, the health benefits of cycling are largely positive.
Who is most at risk during pollution peaks?
Children, pregnant women, the elderly, people with asthma or suffering from cardiovascular or respiratory diseases are particularly at risk of having a symptom worsen or a disease develop.
In the event of a pollution episode involving particulate matter (PM10), nitrogen dioxide (NO2) and sulphur dioxide (SO2): sensitive and vulnerable people should favour moderate-intensity sports activities;
The general population should reduce or postpone intense sports activities.
In the event of an ozone pollution episode:
Sensitive and vulnerable people should avoid intense sports activities (including competitions) outdoors; they can maintain these activities indoors; the general population can maintain intense sports activities indoors.
How effective it is to wear a mask to protect yourself during a pollution peak?
Only the largest particles carried in the air are stopped by scarves placed over the nose and mouth or paper masks (surgical masks). However, it is not the larger particles that are the most dangerous to health but the finer ones. Wearing this type of protection is therefore useless because it does not stop the fine particles that penetrate our respiratory system and cause pathologies. Most so-called "anti-pollution" masks are designed to protect against particles but do not protect against gaseous pollutants. Their effectiveness depends in particular on a good fit to the face, their maintenance and the presence of a minimum FFP2 standard.
It is therefore important to choose masks that offer different sizes to fit the face and have the best possible airtightness (the maximum amount of air inhaled passes through the filters rather than along the sides or nose), washable masks with interchangeable filters and a quality standard. The Frogmask anti-pollution masks perfectly meet these 3 essential criteria.