What Is Particulate Matter?

Particulate matter – often written as PM - is made up of tiny pieces of dust, dirt, soot, smoke, droplets of liquid and other pollutants. Sometimes you can see the fine particles, but other times they can only be seen with a microscope. Particulate matter is categorized based on size. Larger particulate matter is called PM10 and much finer particulate matter is called PM2.5. PM2.5 is most harmful to your health.

Sources of Particulate Matter

Particulate matter can come from a variety of sources, including:

  • Cooking: activities like broiling, frying, grilling, or using gas stoves
  • Combustion Activities: smoking tobacco, burning candles or incense, and using fireplaces, oil furnaces, and fuel-burning space heaters
  • Household Products: some cleaning products, air fresheners, oil diffusers, and aerosol sprays
  • Hobbies: woodworking, metalworking, 3D printing, making stained glass, and activities including glues and adhesives
  • Biological Sources: mold spores, dust mites, cockroaches
  • Outdoor air: vehicle exhaust, wildfire smoke, campfires, road dust, pollen, mining operations, agricultural activities, and factory emissions. Outdoor particulate matter, also known as particle pollution, can enter buildings through windows, doors, ventilation systems, and small cracks and crevices.

How Particulate Matter Impacts Health

When particles from the air travel deep into your body, they can have a negative impact on your health. PM2.5  is so small they go into the lungs all the way to the air sacs called alveoli. Once there, they can irritate and corrode the alveoli wall, damaging the lungs and causing lung disease. Particulate matter found in the air can make existing lung diseases, like asthma and COPD worse, as well as cause pneumonia, heart disease, stroke and lung cancer.

Watch How Indoor Air Quality Impacts Your Lungs to learn more.

Breathing in particulate matter can cause:

  • Irritation of the eyes, nose and throat
  • Coughing and wheezing
  • Difficulty breathing
  • Worsening of asthma and other chronic lung diseases
  • Heart disease
  • Stroke
  • Lung cancer

The burden of polluted air is not equally shared.

Unfortunately, people of color are exposed to more indoor air pollutants, including particulate matter. People of color experience greater-than-average exposures from source types, causing 75% of overall exposure. This disparity holds true across states and urban and rural areas, income levels, and exposure levels.

How to Protect Against Particulate Matter

There are several ways to reduce particulate matter and improve the air quality indoors. The first step is to always identify and remove the source of the pollutant, also known as source control.

  • Avoid burning candles, incense or other items in the home
  • Only smoke or use vape devices outdoors
  • Don’t use wood burning stoves or fireplace unless it is a primary heat source
  • Use safe wood-burning practices if you must use a woodstove or fireplace
  • Never use unvented fuel-burning stoves, fireplaces or space heaters indoors
  • Maintain fireplace, woodstove, and other fuel-burning appliances
  • Close doors, windows when outdoor PM levels are high
  • Open doors and windows for 15 minutes each day
  • Install and use exhaust fans when cooking
  • Upgrade the building’s furnace filter to a higher MERV rating, preferably 13 or higher.
  • Change filters every 30 days or so
  • Use a portable air cleaner, or air purifier, to clean the air in a single room

Reduce Particulate Matter by Ventilating Your Home

Ventilate your home by getting fresh air into your home, filtering the air that is there, and improving air flow. Good ventilation, along with other prevention actions can help prevent you and others from getting and spreading COVID-19 and other respiratory viruses. Use CDC’s Interactive Home Ventilation Tool to learn how you can decrease the level of COVID-19 virus particles during and after a guest visits your home.
Use the tool

Page last updated: November 2, 2023

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