Particulate matter (PM) is a pollutant in the air we breathe. PM varies in size from visible to the naked eye to so small it can only be detected using an electron microscope. Understanding where PM comes is important to preventing or reducing the effects it has on both people and the environment.
What is Particulate Matter?
Particulate matter (PM) or particle pollution, is a mixture of solid particles and liquid droplets found in the air. PM differs in chemical composition, shape and size.
Broken down by size, particulate matter consists of:
- PM10: Particles that are 10 micrometers in diameter or smaller are called PM10.
- PM2.5: Particles that are 2.5 micrometers in diameter or smaller are called PM2. These particles are also referred to as “fine particles” because of their ability to penetrate deeper into the lungs than PM10 particles.
- “How small is 2.5 micrometers? Think about a single hair from your head. The average human hair is about 70 micrometers in diameter – making it 30 times larger than the largest fine particle.” (Environmental Protection Agency, EPA) See the graphic below courtesy of the EPA:
Potential Symptoms of Particulate Matter Exposure
Concerns about PM are generally due to the variety of symptoms it may cause, and its ability to do so. PM10 can pass through the throat and nose into the lungs, while PM2.5 can penetrate deeper into the lungs.
Symptoms may vary based on exposure levels and sensitivities to particulate matter. Not all individuals exposed PM will experience symptoms. Below, we’ve listed some of the potential symptoms associated with exposure to PM.
- Eye, nose and throat irritation
- Coughing
- Irregular heartbeats
- Decreased lung function or difficulty breathing
- Aggravated asthma
- Nonfatal heart attacks
- Premature death in people with heart or lung disease
Who is Most at Risk from Particulate Matter?
Certain groups of people are more sensitive than others to particulate matter exposure. Below we’ve listed groups with sensitivities that may make them more susceptible to symptoms:
- People with lung disease. Those with lung disease may have trouble breathing and experience increased coughing, chest pain, wheezing and fatigue.
- People with heart disease. Those with heart disease may have serious short-term problems, like a heart attack. Symptoms may be a sign of a serious problem, such as chest pain or tightness, rapid heartbeat, loss of breath, and increased fatigue.
- Elderly. Older adults or elderly tend to have more pre-existing conditions, such as lung or heart disease. With their age and pre-existing conditions, exposure to PM may contribute to a premature death.
- Children. Children’s lungs are still developing. With exposure to PM, their lungs are at risk of reduced growth.
- Asthmatics. Those with asthma may experience an increase of asthma symptoms and emergency room visits.
What Are the Sources of Particulate Matter?
Particulate matter can be sourced both naturally and by human activity and occur both indoor and outdoor depending on the source. Sources of PM include the following:
- Wildfires
- Dust storms
- Volcanic eruptions
- Sea spray
- Natural PM may include components of biological sources
- Burning of gas in motorized vehicle engines
- Industrial processes
- Power generators
- Burning wood, candles and incense
- Stoves, heaters, fireplaces and chimneys
- Tobacco smoke
How Can I Prevent or Reduce Exposure to Particulate Matter?
Since particulate matter sources can originate from both outdoor and indoor, there are different ways to prevent or reduce it. We’ve broken up these methods into the two categories below:
Outdoor Particulate Matter Exposure
- Avoid high-traffic roads, such as highways.
- Avoid unnecessary idling of vehicles, especially in enclosed spaces, like a garage.
- Reduce time spent outdoors during times with high pollution.
- Consider purchasing electric vehicles.
Indoor Particulate Matter Exposure
- Ensure all fuel-fired combustion appliances are vented to the outdoors. Appliances include stoves, heaters and furnaces. Make sure turn on the exhaust fan while cooking.
- Stoves, fireplaces or space heaters without vents should be avoided.
- Have a trained professional inspect, clean and tune-up central heating systems annually. Central heating systems include furnaces, flues and chimneys.
- Regularly change the filters on central heating and cooling systems, and air cleaners according to the manufacturer's instructions.
- Avoid smoking indoors or in enclosed spaces, like a car.
- Limit burning of wood, candles and incense. When you do use them, ensure proper ventilation.
- Use a central forced air system, such as an air purifier. Follow the manufacturer’s instructions on maintenance.
Environmental Effects of Particulate Matter
Particulate matter may also affect the environment. The environmental effects of PM may vary based on their chemical composition and where they are carried to, since PM can be carried over long distances. Environmental effects include:
- Adding to the effects of acid rain.
- Contributing to visibility or “haze”.
- Making lakes and streams acidic
- Impacting the diversity of ecosystems.
- Depleting nutrients in soil.
- Damaging sensitive forest and farm crops.
- Changing the nutrient balance in coastal waters and large river basins.
