Seven Somewhat Surprising Sources Of Air Pollution

Where does air pollution come from? The most harmful form of air pollution, called "Fine Particulate Matter", comes from a variety of sources. Some of those sources are naturally occurring, but most of them are human-made. (Yay humans!)

 

The leading cause of PM pollution impacting the air quality adversely comes from something that many of us use regularly, even if we are ashamed to admit it. Yes, we're talking about this stuff:

More info: cleanairresources.com

Ok, this might look like an illicit powdered substance, and yes, I use it regularly (for gardening). In fact, it is one of the ingredients of coke, but not the drug... the gas. This stuff is called Ammonium Sulfate, and it's used in the production of a the world's most prevalent source of air pollution:

The Ammoniums refer to Ammonium Sulfate (NH4)2SO4) and Ammonium Nitrate (NH4NO3), which together comprise the single largest sources of fine particulate air pollution. In fact, these two sources contribute about 50% the total volume of harmful fine particulates in our air. Ammonium particulates tend to make their way into the air (and therefore our lungs) when used as fertilizer, especially when previously-fertilized fields are burned.

Speaking of, here's the next big pollution source:

This category of pollution refers to two of my favorite activities in the winter and summer, respectively: sitting around a toasty fireplace, and getting together for a BBQ. Burning biomass in a controlled manner can account for around 15% of fine particulate pollution, similar to the percentage caused by:

You probably guessed this one. It's true. Enough particulates slip through our exhaust systems that emissions from diesel and gasoline engines together make up around 15% of pollution particles in the air. And all those cars and trucks rolling across the ground add in their own way to another primary cause of air pollution:

A large percentage of the pollution found in our air is caused by a source that’s pretty much unavoidable. Yes, we're talking about dirt. Dirt, dust, or as it's referred to in scientific circles, “Crustal Matter”, accounts for around 12% of microscopic particulates measuring 2.5 micron or less. This source of pollution has been identified by studies from Finland, to Korea, to the American midwest. It's clear that wherever you go, dirt is a major contributor to air pollution, just like this next source:

Like the Ammoniums, pollution from oil combustion doesn’t come from one single activity. Industrial manufacturing, space heaters, and even home heating systems (in cities like Seattle, a substantial number of homes use oil heat). Particulate matter from oil combustion can make up between 5–15% of air pollution particles. That's a lot of grease.

And what goes well with grease?

That’s right. As amazing as salt tastes, it just can't seem to escape getting a bad rap. The interesting thing about salt as a source of air pollution is that you can't really escape it. Near an ocean? The sea-salt is going to make it way into the air. Up in the mountains? The salt used to melt road ice is going to make its way into the air! Everyone’s favorite flavor enhancer may be last on the list, but it still contributes between 2–3% of fine particulate pollution overall.

These are the main sources, but with the onset of global warming and increasingly regular wet and dry cycles, we'd be remiss to leave out a major, if not consistent, contributor to particulate pollution:

During the months when pollution from wildfire smoke is abundant, it quickly becomes the largest individual contributor to fine particulate matter. How large? On a typical California day during the summer of 2018, forest fire smoke was the source of an incredible 73% of all air pollution.

Here's a chart showing the distribution of air pollution particles without factoring in forest fire smoke.

Here's the same graph, but with wildfire smoke added. Pretty insane.

The takeaway here is that most of the time, there is no one source of air pollution. Forest fire pollution, on the other hand, can turn into a dominant form of pollution that can wreak havoc on our lungs and health. This makes it especially important that we do what we can do prevent forest fires. Because I’m definitely not giving up my salt.

Finally, when the air quality is extremely bad, consider using a respirator face mask to protect yourself and your lungs from the negative effects of particulate matter.

Ok, maybe not a mask like this one. Shop around... there are some good options out there that won’t make people think there’s been an outbreak (although we hear there’s an awful lot of this pretty nasty stuff called “dirt” just lying around… stay safe!).