Fine particulate matter, or PM2.5 (particles 2.5 microns (µm) in size and smaller), is a mixture of microscopic particles of solids or liquids in the air. PM2.5 is released into the air when burning fossil fuels to heat buildings, generate electricity, and run motor vehicles. Other sources of PM2.5 include locomotives, airplanes, ships, industrial processes, waste handling, asphalt production, commercial cooking, and burning wood.
This past February, the Environmental Protection Agency (EPA) announced new regulations to strengthen National Ambient Air Quality Standards (NAAQS) for fine particulate matter. Effective May 6, 2024, the regulation lowers the primary annual PM2.5 standard to 9.0 micrograms per cubic meter to better protect human health. The threshold for the “Moderate” category of the Air Quality Index (AQI) has been lowered to reflect the new NAAQS. Along with strengthening the annual PM2.5 standard, EPA is enhancing monitoring (PDF) of PM2.5 near vulnerable populations with increased health risks from PM2.5 exposure, such as those living in environmental justice communities.
States need to determine if they comply with the new PM2.5 NAAQS standard and develop a plan to bring any noncompliant or nonattainment areas into compliance. Once these implementation steps are completed, states with nonattainment areas must prepare planning assessments within six years to show attainment of the new PM2.5 standard.
Improved Health for All
Exposure to PM2.5 can adversely affect the heart, lungs, and nervous system. Due to its small size, PM2.5 can penetrate deep into the lungs and enter the bloodstream. Some small particles can travel throughout the body to other organs, such as the kidneys or brain. Many negative health effects are associated with short- and long-term exposure to PM2.5. Children, older adults, and those with pre-existing lung and heart disease are especially vulnerable to the effects of air pollution. The new annual PM2.5 standard will result in significant public health benefits (PDF), including decreases in asthma symptoms, lost workdays, and premature deaths by 2032.
Whether choosing to carpool or taking steps to conserve energy at home, individual actions can make a big difference in reducing PM2.5 levels. You can also switch to zero-emission energy sources, such as subscribing to a community solar project or purchasing an electric or hybrid vehicle when it’s time for a new car. By practicing clean air habits and checking the AQI forecast before heading out, you protect your health and keep the air clean for all to enjoy.
