Q&A: Canada Wildfire Smoke

[New York mid-day skyline on June 7, 2023. Photo from EarthCam]

Question: Why are we getting smoke from Canada’s wildfires here on the east coast? Those fires are hundreds of miles away. What’s most surprising to me is that, over all that distance, the smoke hasn’t really thinned out or dispersed. I’m at the south end of New Jersey and just started wearing my N95 mask again while outside. — WT, Cape May, NJ

Answer: Yes, you are around 500 miles from most of those fires. Unfortunately, there is a large low pressure system centered just off the coast of Massachusetts, and it’s being reinforced by another low off the coast of North Carolina. Take a look at the national weather map for June 8, 2023:

Low pressure systems cause the atmosphere to circulate in a counter-clockwise direction (in the Northern Hemisphere). These systems can span diameters up to 1000 miles, and the one that dragged the smoke down from Canada was around that size. Here’s the NOAA satellite time-lapse of that motion, taken by the GOES-East satellite:

And the smoke has indeed “thinned out” even though it’s still pretty bad. You can see that up in Quebec it’s far worse. As the weather patterns shift, that wildfire smoke will head in other directions. But until all those fires are extinguished, (and as of June 8, 2023 there are 232 fires 0% contained) that smoke has to go somewhere. So, unfortunately, it may return to New Jersey.

Rain can wash smoke particles from the air, but otherwise they can remain aloft for weeks and be carried for hundreds to thousands of miles. Many particles of smoke are less than 2.5 μm in diameter. These are the PM2.5 (particulate matter 2.5 μm) that you hear about in Air Quality Index (AQI) warnings. They are hazardous to your health.

Take those AQI warnings seriously, even if you’re in good health. Wear a mask outdoors if you have to leave the house. Keep your HVAC on recirculate if possible, and incorporate a HEPA filter or indoor air purifier if you can afford it. If you can’t afford it, consider a DIY air purifier which can be assembled for $20 — the cost of the filter if you already have a box fan.

This will happen again as the climate evolves. Best to be prepared. You can monitor the AQI at your location in real time on the PurpleAir website. Just click on Map / Real-time Map and it’ll load the data for your area. I have that site bookmarked. You should too.

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