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Air Quality: Particulate Matter (PM) 101

May 02, 2023 09:00 AM

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You probably remember learning the basics of air pollution in school; words like ozone, CFCs, acid rain, greenhouse gases, and smog filled textbooks, homework, and quizzes. We learned that aerosols were harmful to the ozone layer, and we saw dramatic before-and-after photos of cities completely hidden behind heavy black clouds.

While most of us no longer have Science tests to pass, there are a few important air quality terms we should all know and pay attention to. It's likely you may have seen an Air Quality Alert from DEP or noticed your weather app warning about unsafe air pollution. When thinking about air quality or air pollution, it's important to understand particulate matter, or PM.

What is particulate matter? US EPA defines it as a mixture of solid particles and liquid droplets found in the air. Some particles, like dirt, dust or smoke are large enough to be seen with the naked eye, while others can only be detected using a special microscope.

The PM size which poses the greatest risk to health, PM 2.5, simply means that the particles in the matter are about 2.5 micrometers or smaller. How big (or small) is 2.5 micrometers? EPA tells us to think about a single human hair, which is approximately 70 micrometers in diameter. That means the particles in PM 2.5 are about 1/30th the diameter of a single strand of hair. 

PM 2.5 Air Pollution

Because the particles are so small, it's easy to see how they can be inhaled into our lungs, making it hard to breathe and even causing health problems. The smaller the particle, the deeper into our lungs and bloodstream they can travel.

This type of pollution also contributes to environmental damage, such as increasing the acidity of our waters and depleting nutrients in our soil. Have you ever noticed that the skyline or mountains seem less clear on some days? Pollutant particles contribute to haze and reduce our visibility, often leading to unsafe conditions.

What can you do on days when particle pollution levels are expected to be high?

  • Drive less by carpooling or using public transportation
  • Combine errands to reduce vehicle trips
  • Limit engine idling
  • Refuel cars and trucks after dusk
  • Conserve electricity by setting air conditioning to a higher temperature and turning off lights that are not in use
  • Reduce or eliminate fireplace and wood stove use
  • Avoid using gas-powered lawn and garden equipment
  • Avoid burning leaves, trash and other materials

So how can you protect yourselves and family? Get air quality data where you live at and stay up to date on Air Quality Action Days.  

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