Air Pollution - Particulate Matter



Why do we measure air pollution – particulate matter?

Particulate matter pollution is a common proxy indicator for air pollution.(1) Fine particulate matter pollution from industrial facilities, vehicles, smoke, and other emissions, can be inhaled deep into the lungs and spread throughout the body, increasing a person’s risk for health conditions like lung cancer, heart attacks, stroke, asthma, allergies, and respiratory infections.(1-5) Older adults, infants, pregnant women, and those with pre-existing health conditions are especially at risk of experiencing health problems from air pollution.(3) On average, lower-income communities tend to be exposed to higher levels of air pollutants because they are often closer to facilities that contribute to air pollution.(6,7) Measuring air quality helps us address pollution and track reductions.

How do we measure air pollution – particulate matter?

This metric includes the average daily concentration of fine particulate matter (PM2.5) in the air over the course of a month.

Strengths of Metric

Limitations of Metric

Monitoring air quality helps us target areas of high air pollution and track reductions for congressional districts—which lowers the risk of mortality.(5)

This metric only measures fine particulate matter and does not assess specific toxic pollutants.(8)

Congressional district measures are estimated using data from a network of sensors around the country and are less accurate in areas with fewer sensors.

Larger geographies may hide differences in fine particulate matter exposure.

This metric does not specify the source of pollutants.


Daily PM2.5 levels are estimated and averaged over the course of a month to control for seasonal variation in air pollution. This metric was calculated by aggregating estimates from smaller geographies to the congressional district level. For more information on the calculation, please refer to the Congressional District Health Dashboard Technical Document.

Data Source

The data were created by merging ground observations from the US Environmental Protection Agency (EPA) Air Quality System (AQS) network with computer model prediction from the National Oceanic and Atmospheric Administration (NOAA) National Air Quality Forecast Capability (NAQFC) by the George Mason University air quality team. Multi-year data are available for this metric. For more information, please refer to Using Multi-Year Data: Tips and Cautions.

Years of Collection

Calculated by the Dashboard Team using data from 2022, 1 month average estimate.


  1. Centers for Disease Control and Prevention. Outdoor Air. Updated September 8, 2017; Accessed February 28, 2018.

  2. Centers for Disease Control and Prevention. Particle Pollution. Updated July 22, 2016; Accessed February 28, 2018.

  3. Mannucci PM, Harari S, Martinelli I, Franchini M. Effects on health of air pollution: a narrative review. Intern Emerg Med. 2015;10(6):657-662.

  4. Pope CA, Dockery DW. Epidemiology of particle effects. In: Air pollution and health. Elsevier; 1999:673-705.

  5. Laden F, Schwartz J, Speizer FE, Dockery DW. Reduction in fine particulate air pollution and mortality: Extended follow-up of the Harvard Six Cities study. Am J Respir Crit Care Med. 2006;173(6):667-672.

  6. Ard K. Trends in exposure to industrial air toxins for different racial and socioeconomic groups: A spatial and temporal examination of environmental inequality in the U.S. from 1995 to 2004. Soc Sci Res. 2015;53:375-390.

  7. Hajat A, Hsia C, O'Neill MS. Socioeconomic Disparities and Air Pollution Exposure: a Global Review. Curr Environ Health Rep. 2015;2(4):440-450.

  8. Perlmutt L, Stieb D, Cromar K. Accuracy of quantification of risk using a single-pollutant Air Quality Index. J Expo Sci Environ Epidemiol. 2017;27(1):24-32.

Last updated: February 20, 2024