Particulate Matter (PM-2.5)

Data Disclaimer

The above air quality data are typically displayed within one to three hours of their collection and are provided for general public awareness only. 

Understanding PM2.5

woman standing beside large metal air monitor outside

Particulate matter (PM) is a complex mixture of extremely small particles and liquid droplets. Particle pollution is made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles.

The size of particles is directly linked to their potential for causing health problems. The EPA is concerned about particles that are 10 micrometers in diameter or smaller because those are the particles that generally pass through the throat and nose and enter the lungs. Once inhaled, these particles can affect the heart and lungs and cause serious health effects. High levels of particulate matter can cause visible air pollution, not only affecting our health, but our natural scenery as well.

PM2.5 is particulate matter less than 2.5 micrometers (100 times thinner than a human hair) and are measured in outdoor ambient conditions. PM2.5 is considered “inhalable fine particles," and can be found in smoke and haze.

Health Effects of PM2.5

Particle pollution, especially PM2.5, contains microscopic solids or liquid droplets that are so small that they can get deep into the lungs and cause serious health problems. Numerous scientific studies have linked particle pollution exposure to a variety of problems, including:

  • Premature death in people with heart or lung disease
  • Nonfatal heart attacks
  • Aggravated asthma
  • Decreased lung function
  • Increased respiratory symptoms, such as irritation of the airways, coughing or difficulty breathing.

People with heart or lung diseases, children and older adults, are the most likely to be affected by particle pollution exposure. However, even if you are healthy, you may experience temporary symptoms from exposure to high levels of particle pollution.

Sources of PM2.5

Sources of PM2.5 include all types of combustion, including motor vehicles, power plants, residential wood burning, forest fires, agricultural burning, and some industrial processes. PM2.5 can be made up of toxic organic compounds or heavy metals emitted from vehicle exhaust and brush fires, forest fires or burning yard waste.

Monitoring PM2.5 in Aspen

Aspen’s particulate air quality monitor is collocated with Colorado Department of Public Health and Environment’s PM-10 monitors on the roof of the Yellow Brick building, located at 215 North Garmisch. This location provides a good indication of the overall particulate levels for Aspen. By monitoring PM2.5 we can determine our compliance with the EPA’s 24-hour standard of 35 ug/m3 (micrograms per cubic meter). The City of Aspen began monitoring PM2.5 in November of 2014.

Questions? Contact us at, 970-920-5039