Air Quality

The United States has made significant progress in reducing air pollution levels since the 1970s, when the Environmental Protection Agency (EPA) began regulating air quality. However, poor air quality continues to pose risks to public health in areas across the United States. EPA has reported that about 40% of the U.S. population lives in areas where air pollution levels exceed limits set to protect public health. In addition, some communities are increasingly concerned about the health effects of air toxics as well as non-industrial sources of air pollution, such as wildfires. In particular, the U.S. has recently experienced some of its worst wildfire seasons on record, creating unhealthy smoke that affected air quality for tens of millions of Americans.

The Clean Air Act, as amended, establishes the legal framework for air quality management in the United States. Under the Clean Air Act, EPA seeks to protect and enhance the quality of the nation's air and protect public health and welfare from the harmful effects of air pollution.

Key issues related to managing air quality include:

• Monitoring. EPA and state and local agencies cooperatively manage the ambient air quality monitoring system, with each playing different roles in its design, operation, oversight, and funding. For example, EPA establishes minimum requirements for the system, and state and local agencies operate the monitors and report data to EPA. However, EPA and state and local agencies face challenges meeting evolving air quality information needs, such as information on local air pollution hot spots and air toxics. To address these challenges, EPA should develop a modernization plan for the air quality monitoring system.

Air Quality Monitoring Site

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• IT Systems. EPA primarily uses two legacy information technology (IT) systems to manage outdoor air quality data that tribal, state, and local air monitoring agencies collect. This data is critical to efforts to reduce air pollution and related public health risks—for example, it helps identify areas that don’t meet air quality standards and communicates information about air pollution levels to the public. The aging IT systems for air quality data present maintenance and usability challenges for EPA and other users. EPA is considering replacing these systems with a new one, and the agency should document the need for and cost of a new system.
• Wildfire smoke. EPA has identified smoke from increasingly frequent catastrophic wildfires as a climate change vulnerability that may affect its ability to meet mission and air quality goals. But EPA’s efforts to help communities prepare for and respond to wildfire smoke episodes have been ad hoc and spread out across the agency. EPA could better coordinate internally on these efforts. EPA could also enhance its role in supporting certain wildfire risk mitigation efforts, such as “prescribed burns,” that land managers implement to help decrease the intensity of wildfires. For example, EPA—in some cases with the Forest Service and Department of the Interior—could provide information about reducing wildfire smoke risks and incentivize and support wildfire risk mitigation at the tribal, state, and local levels.

 Examples of Wildfire Smoke Effects on Air Quality

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• Sources. Technological improvements have led to the development of air quality sensors that can be deployed virtually everywhere, including on fences, cars, drones, and in clothing. This technology can help fill in air quality monitoring gaps and provide additional information to understand air pollutants that can harm public health and the environment. However, sensors are not yet available for some air toxics and ensuring the quality and appropriate interpretation of sensor data can be challenging. Policymakers (legislative bodies, government entities, academia, industry, and other groups), could take certain actions—such as supporting innovation in sensor technologies or improving access to guidance on sensor use—to help address challenges to developing and using sensors.