Particulate matter (PM) levels refer to the concentration of tiny solid particles and liquid droplets suspended in the air. Also known as particle pollution, PM levels indicate overall air quality. These particles originate from various sources and pose public health concerns. Understanding PM levels helps in assessing the air we breathe daily.
Understanding Particulate Matter
Particulate matter is a complex mixture of solid or liquid particles. These particles vary widely in size, shape, and chemical composition, including dust, soot, smoke, and liquid droplets. They are classified by their diameter for air quality regulation.
Two main categories are PM10 and PM2.5. PM10 refers to inhalable particles 10 micrometers or less in diameter. These coarse particles enter the lungs through the throat and nose.
PM2.5, also known as fine inhalable particles, have diameters 2.5 micrometers or less. A human hair is roughly 100 micrometers wide, meaning about 40 fine particles could fit across its width. These smaller particles are more hazardous due to their ability to penetrate deeper into the lungs and potentially enter the bloodstream.
Common Sources of PM
Particulate matter originates from natural and human activities. Natural sources include wind-blown dust, pollen, smoke from wildfires, and volcanic eruptions.
Human activities account for a substantial portion of PM pollution. Vehicle emissions from gasoline, oil, and diesel fuels are a primary source, along with industrial processes and power plants. Burning wood in residential fireplaces and stoves, agricultural operations, and construction or demolition also release particles. Some particles are directly emitted, while others form in the atmosphere through chemical reactions of gases like sulfur dioxide and nitrogen oxides from combustion sources.
Health Impacts of PM Exposure
Exposure to particulate matter can lead to a range of health issues. Short-term exposure (hours to days) can trigger irritated eyes, nose, and throat, coughing, phlegm production, and shortness of breath. It can also aggravate existing lung conditions like asthma and chronic bronchitis, and in individuals with heart disease, it has been linked to heart attacks and irregular heartbeats.
Long-term exposure (many years) has severe consequences. It is associated with reduced lung function, chronic respiratory diseases like chronic obstructive pulmonary disease (COPD), and an increased risk of lung cancer. It also heightens the risk for cardiovascular diseases, including heart disease and stroke, and can lead to premature death. Children, older adults, individuals with pre-existing heart or lung conditions, and diabetics are more susceptible to these effects.
Reducing Your Exposure to PM
Taking steps can help reduce exposure to particulate matter. Check local air quality reports, often available through an Air Quality Index (AQI). Limit outdoor activities when pollution levels are high. An AQI value above 100 indicates unhealthy air for sensitive groups, while values over 150 indicate unhealthy air for everyone.
When outdoor PM levels are high, stay indoors with windows and doors closed to prevent particles from entering your home. Use high-efficiency portable air cleaners with HEPA filters to remove particles from indoor air. Upgrade your home’s HVAC system filter to a higher MERV rating, preferably 13 or higher, to improve indoor air quality.
Other actions include:
- Avoiding indoor burning of candles, incense, or wood in unvented stoves.
- Wearing an N95 particle mask during outdoor tasks that generate dust or smoke, such as using leaf blowers.
- Maintaining proper ventilation when cooking.
- Regularly cleaning surfaces with a damp mop or a vacuum cleaner with a HEPA filter.