After the northern United States, it is Europe that is about to be affected by the smoke from the megafires that are currently engulfing Canada. In the grip of massive forest fires, the country has been suffocating for long weeks. Montreal is currently the most polluted place in the world and a “smog” warning has been issued by Environment Canada in several regions of Quebec, where 81 wildfires continue to be active, 27 remaining out of control. The Canadian Interagency Wildfire Center lists 470 active fires across the country, where more than seven million hectares have burned since January.

Neighboring territories are not spared: photos of the New York sky, turned orange by smoke, have gone around the world, and the Old Continent too may soon be affected. The fine particles drained by this toxic smoke, carried by the sea winds, could soon reach the French coasts.

Charlotte Lepitre, project manager for Atmo France, the federation of associations responsible for monitoring air quality, answered questions from Le Point.

Le Point: Do we know where and when this pollution from forest fire smoke will arrive in Canada?

Charlotte Lepitre: No, not precisely, because it will depend on the ocean weather, wind speed and direction as well as precipitation. We are on high alert, but the vast majority of pollution will disappear over the Atlantic. The largest particles will fall back there, due to their weight, or thanks to the rain, before reaching us.

What are these toxic fumes made of and how long will they stay in the atmosphere?

Pollutants are composed of soot carbon and particles of different sizes resulting from the poor combustion of organic matter. In our case, carbon soot and larger particles will reach us only a little. Too heavy, they will fall on the way. We will probably have small fine particles of organic matter, invisible to the naked eye if they are in limited quantity: so there will be no orange skies like in New York, nor smog, unless the ocean weather change suddenly, but it is unlikely.

Their presence in the air also depends on the weather. If it starts to rain, the particles will only stay for a few hours, while if the weather is dry, they can last for several days. The wind is also an important factor: if it continues to blow, the particles will continue their way towards northern Europe. If, on the contrary, an anticyclone blocks the winds, they can stagnate in the air for several days in a row.

What are the health risks ?

The quantities of particles arriving at us from Canada will be reduced in number, unrelated to the pollution that we already produce on our territory, and which remains the major problem. However, the danger with these ultrafine particles is that they are small and enter deep into the body, passing through blood barriers. They will thus accumulate over the long term in our organs, in particular in the heart, where they contribute to increasing the risk of stroke, and again in the brain, where they increase the risk of developing Alzheimer’s and Parkinson’s disease. .

In the short term, they irritate our airways, which have already been strained by previous peaks of ozone, fine particle and pollen pollution in recent months. This can therefore promote the development of asthma and cough, or even respiratory infections for the most fragile. But again, it’s not Canadian pollution that’s dangerous: it’s mostly that it adds to our own pollution, which is already far too high.

Its impact on the environment, on the other hand, will undoubtedly be minimal: these pollutants can suffocate certain plants, but they do not have a major impact when they fall to the ground and mix with other organic materials. If the organic matter that makes up the fine particles is acidic, which we don’t yet know, it can acidify oceans and rivers. I will not go so far as to say that this pollution has no environmental impact, but this is in any case less worrying than the consequences on human health.

How to protect against it?

Unfortunately, there is not much to do. Masks are not recommended for ultrafine particles, as they do not filter them properly. Worse, they can block larger particles, which remain in our superficial airways and act as a barrier by preventing the finest from reaching our deepest airways. Putting on a mask therefore amounts to leaving them the field free, which is not indicated.

Have you ever experienced a similar situation?

Yes, this happens regularly. When there are volcanic eruptions, in Iceland, for example, fires in Italy or Greece, or when industrial pollution from Germany and Italy is brought to us by the wind… Air pollution does not has no border.