Opportunities to Better Sustain and Modernize the National Air Quality Monitoring System GAO-21-38: Published: Nov 12, 2020. Publicly Released: Dec 7, 2020. “The national ambient air quality monitoring system measures air pollution levels at fixed locations across the country. The U.S. Environmental Protection Agency, state, and local agencies cooperatively manage this system’s aging infrastructure. Our interviews and review of literature found that air quality managers, researchers, and the public need more information to understand health risks from air pollution. For example, they need additional information on pollutants found near industrial facilities and the performance of low-cost sensors. We made 2 recommendations, including that EPA develop a plan for modernizing air quality monitoring.