February 7, 2024
Mapping Soot and Smog Pollution in the United States
Under the Clean Air Act, the U.S. Environmental Protection Agency must set standards that protect public health from common air pollutants, such as fine particulate matter (also known as soot) and ground-level ozone (also known as smog).
On Feb. 7, the EPA strengthened the annual particulate matter standard from 12 micrograms per cubic meter to a more protective standard of 9 µg/m3. This will reduce air pollution across the country and ensure that states respond to the ongoing public health and environmental justice crisis, saving thousands of lives and avoiding 800,000 asthma symptom cases every year. Thank the EPA for listening to the public and strengthening its standards for soot pollution.
Though we know about many areas that have unsafe levels of air pollution, we don’t know the full extent of the problem. Many urban and rural areas — about two-thirds of counties in the United States — lack air monitors. This means many communities have no way of knowing the state of the air they breathe. Rigorous monitoring is critical for protecting public health.
The Soot Standard: Measures average soot levels over one year. In 2024, EPA updated the standard to a more protective 9 micrograms per cubic meter from 12 µg/m3.
For more than a decade, Earthjustice has filed legal actions on behalf of our clients to compel the EPA to follow the Clean Air Act’s requirements to protect the public’s health and well-being from the harms of soot pollution.