Air Quality

Firefighter using water hose on brush fire

National air quality has improved since the 1990s, but many challenges remain in protecting public health and the environment from air quality problems. Air pollution in the United States poses a public health threat affecting potentially millions of people throughout the country. It is associated with health problems that include asthma, increased emergency department visits and hospital stays for breathing and heart problems and increases in illnesses such as pneumonia and bronchitis.

We Track That

Since the 1950s, air quality has been a major public health and environmental concern. Local, state, and national programs have helped us learn more about the problems and how to solve them. Federal, state, local, and tribal air agencies operate and maintain a wide variety of outdoor air monitoring systems across the United States. Many of these systems serve several environmental objectives. At a basic level, they let us know how clean or polluted the air is, help us track progress in reducing air pollution, and inform the public about air quality in their communities. The Tracking Network hosts and uses data from some of these sources to help paint a more complete picture of air quality in the United States.

Types of Data

CDC works closely with the U.S. Environmental Protection Agency, the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Association (NOAA), and the National Weather Service to provide air quality data on the Tracking Network and to better understand how air pollution affects our health.

Monitor + Modeled Air Data
After careful study, EPA and CDC found that air pollution modeled predictions are very similar to actual monitor data in areas where the two can be compared. In some areas, the modeled data underestimates or overestimates the air pollutant concentration levels when compared to the Air Quality System (AQS) monitoring data. Therefore, the best way to use modeled air data is in conjunction with actual monitoring data. On the Tracking Network, both AQS and modeled datasets are available to track possible exposures to ozone and PM2.5, evaluate health impacts, conduct analytical studies linking health effects and the environment, and guide public health actions.

  • Ozone Days Above Regulatory Standard
    The number of days in which the daily maximum 8-hour average ozone concentration exceeds a standard provides an indication of short-term spikes in ozone concentrations. This may give you an idea of how many days per year you may be exposed to unhealthy levels of ozone.
  • PM2.5 – Days Above Regulatory Standard
    These data help summarize short-term trends in particle pollution concentrations. This may give you an idea of how many days per year you may be exposed to unhealthy levels of particulate matter.
  • Annual PM2.5 – Level
    These data help summarize long-term trends in particle pollution concentrations. This will give you an idea of what the yearly level of PM2.5 is in an area.

Health Impacts of Fine Particles in Air: Mortality Benefits Associated with Reducing PM2.5 Concentration Levels
To calculate these data, CDC is using EPA’s BenMAP with modeled air data for fine particulates, death data from CDC’s National Center for Health Statistics, population data from the U.S. Census Bureau, and information from scientific literature about the relationship between change in air pollution and how that influences health effects. These data summarize the estimated number of deaths prevented and percent change in deaths associated with lowering PM2.5 concentration levels. The Tracking Network lets the user sort many results by categories of county-level sociodemographic variables such as percentage of population in poverty, percentage of adult smokers, population density, and more.

Air Toxics
Data from EPA’s National-Scale Air Toxics Assessment (NATA) are used to develop the air toxics indicators for the Tracking Network. Air toxics measures can be used to

  • prioritize emission sources as potential targets for risk reduction activities and further study,
  • identify locations of interest for further investigation, and
  • show the geographic distribution of air toxics.

Forecasted Air Quality
CDC’s Environmental Public Health Tracking Program collaborated with the National Aeronautics and Space Administration’s (NASA) Goddard Space Flight Center to develop this data set. The forecasts included in this indicator can help decision-makers and other stakeholders anticipate harmful air pollution exposures several days in advance. This composition forecast data set is a research-grade product and should be used only in circumstances where substantial error in the estimates does not pose a significant threat to human health or other operational priorities.

Wildland Fires
This indicator displays locations of predicted surface smoke concentrations from wildfires that are layered on top of county- and census tract-level measures of access to care and social vulnerability, health status, annual air quality levels, or population characteristics.

Data Highlight
Air Quality - Wildland Fires - Visual of Tracking Network's Data Explorer's Wildfire Smoke Tool

Will your area be affected by wildfire smoke? The Tracking Network has data that can show the predicted movement of wildfire smoke based on wind patterns and other factors.

Visualizing Real Time Wildland Fire Smoke using CDC's Tracking Network Data Explorer tool - animated graphic showing website on laptop.

Data in Action

The health effects of air pollution are influenced by social, demographic, and economic factors. The Tracking Network allows users to analyze factors that may increase vulnerability to health effects including income, race and ethnicity, health insurance status, and age. Tracking air quality in a standard way over time can help us

  • track potential exposures and evaluate health impacts.
  • estimate the positive health impacts that could be achieved with a change in outdoor air quality.
  • prioritize emission sources as potential targets for risk reduction activities and for further study.
  • identify locations of interest for further investigation.
  • assist public health practitioners and emergency responders identify populations at risk for exposure to wildfire smoke and make informed decisions before, during, and after wildfire smoke emergencies.

Read these success stories to learn about air quality related work happening in our funded Tracking Programs.

California | Colorado | Florida | Maine | Maryland | Massachusetts | New York | Washington

Learn More

Tracking Resources

Explore Air Quality Data
Data Explorer
screenshot of Tracking Network data explorer tool

Create custom data visualizations, save, & share results

Quick Reports
Asthma Quick Reports web page screenshot

View data in simple charts

API graphic text

Access machine-readable data