If you read or watch any news about pollution, you have probably seen or heard the phrase “PM 2.5.” But what is PM2.5? And how does it impact human health?
In today’s post, I’m going to feature some more environmental health-focused writing. I do a fair share of environmental health writing, but don’t do it very often on this platform. But I want to give it a whirl! So today, right here right now on my blog, we’re going to take a look at what PM stands for, what it is exactly, and why it’s relevant to human health. Get excited!
PM, Defined:
First, let’s start off by defining “PM,” which stands for Particulate Matter. Particulate matter is an air pollution term for a mixture of extremely small solid particles and liquid droplets found in the air, made up of a variety of compounds including acids (such as nitrates and sulfates), metals, organic chemicals, dust, and soil.
Where does PM come from?

PM and PM precursors (which later form PM) come from a variety of human-caused sources, including motor vehicles, power plants, factories, dry cleaners, gas stations. There are also a couple natural sources of PM, including PM emitted from volcanoes and wildfires.
Size Matters:
The size of PM is directly linked to the potential for PM to cause health impacts. Generally speaking, the smaller the particle, the deeper it can penetrate into your lungs, and thus, the more likely it is to do damage. Particles smaller than 10 micrometers in diameter are focused upon, due to their potential to be inhaled and cause detrimental health impacts.
PM 2.5 versus PM 10:

‘PM 10’ refers to dust particles 2.5-10 micrometers in diameter. These particles are smaller than the width of a human hair and can be inhaled.
Particles less than 2.5 micrometers in diameter are known as “PM 2.5,” and are too small to see with the naked eye. PM 2.5 can penetrate deeper into the lungs than PM 10, and thus is more likely to get into the blood supply and be carried throughout the body. Likely due to their high potential to cause negative health impacts, they are the most talked about in popular media.
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