(Washington) The episode of air pollution affecting the northeastern United States this week due to smoke released by fires in Canada is “rare” and “extreme”, explained to AFP Ryan Stauffer, NASA air pollution scientist.
This episode should last for “at least the next two days”, according to the expert on Wednesday.
Question: How out of the ordinary is this event?
Answer : “In the last 20 or 25 years, the only event that comes close to what we are witnessing in the last few days was a similar situation on July 7 and 8, 2002. There were recent fires in Quebec, and the smoke came down directly in the northeastern United States. For many stations (atmospheric pollution readings, editor’s note), it was then the highest pollution ever recorded, in terms of suspended particles.
Sightings made yesterday and today undoubtedly rival this July 2002 event. […] It is extremely rare, and in some places records are broken in terms of the amount of smoke and particulate pollution observed.
This is an extreme event. Certainly, over the last 25 years or so, it’s absolutely exceptional. »
Q: What made it possible?
A: “The unique aspect of this event is the meteorological context, with an anticyclone over central Canada, and a large depression off the northeast coast of the United States.
These two systems combined push the winds south and allow the smoke from these fires to spread directly to the northeastern United States. »
Q: What kind of pollution is it?
A: “What is most worrying about the smoke from the fires are the particles called PM2.5, which means they are less than 2.5 micrometers – or 2.5 millionths of a meter.
These particles are smaller than a hair. […] They are so small that when you breathe them in, they not only irritate your lungs and cause breathing problems, they also enter your bloodstream. So they can cause all sorts of health problems – like increased stress on the heart, heart attacks, strokes – because they circulate through every organ in your body.
We know that when we observe pollution at a red alert level, we can expect more hospitalizations and hospital visits. […] This obviously affects those with prior health issues. People sensitive to pollution, children, the elderly are the most affected.
Over the past two decades, much progress has been made in reducing the emissions that cause PM2.5 pollution episodes. Daily episodes are no longer observed. They must really be linked to an exceptional event, such as the smoke from fires, or the fireworks on July 4 (the national holiday in the United States, editor’s note). »