PM 2.5

The SARS-CoV-2 pandemic gave us the Isolation Apocalypse. Wildfires are giving us the Inhalation Apocalypse. Here’s the report this morning from Purple Air:

The numbers are PM2.5, or particulate matter less than 2.5 micrometers in diameter. The measurement is in micrograms per cubic meter of air. A cubic meter is about 35 cubic feet or 264 gallons. You can fit about two cubic meters of air into the bed of a compact pickup truck. A microgram is really small, 0.000001 gram. A dollar bill weighs about one gram which is one million micrograms.

It’s hard to imagine that 200 micrograms of tiny stuff, dispersed into a big ball of air, could be hazardous to your health. A human hair is about 70 micrometers across, so we are talking about things too small to see with the naked eye. We get a lot of haze around here and that is often the result of suspended fine particles like these. You can’t see them but you know they are there because, off in the distance, visibility is reduced. You are looking at the accumulation of refracted, reflected, and diffracted sunlight. Here in wildfire country we also get large particles—ash and smoke—that you can see just fine!

Fine particulates enter your lungs and get to your bloodstream. It often does not matter what the source is, or what the particles are made of. You don’t want to get that stuff in your body. Wildfires may be organic and all-natural, but you still don’t want to breathe in the by-products. After all, we burn wood in our homes but we have chimneys! If wood smoke was good for you we’d just let it fill the house. And on camping trips everyone stands around the fire pit but if the breeze pushes the smoke in your face you move to a new spot.

So make no mistake particulate pollution from wildfires is a serious health issue. I’m in good health but I’m also 61 so I’m in those risk groups they always talk about. I don’t have heart disease or anything, thank goodness, but I still stay indoors when the numbers are bad. I’ve missed out on walking and bicycle riding, two things I count on to stay healthy, but the trade-off isn’t worth it. Breathing fouled air isn’t good. The fitness gain from outdoor activity is negated by the exposure to pollutants. Worse, exertion means more breathing, which means more bad air in the body. So it’s not a break-even, it’s a loss.

For the PM2.5 air quality measurement 0-50 is considered satisfactory, 51-100 is moderate, 101-150 is unhealthy for sensitive groups, and 151-200 is unhealthy for all. Anything over 201 is obviously very unhealthy and by the time you get to 301 the air is hazardous to breathe.

You can keep track of air quality in several places. The EPA has and I already mentioned Purple Air, which I use all the time. is another useful website for keeping tabs on the air quality.

Let’s hope for some fresh air soon.

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