The U.S. Environmental Protection Agency (EPA) sets acceptable levels for seven air pollutants, and then determines — with the help of states and local air districts — where those standards are or are not met.
As the chart below shows, Yolo-Solano currently meets the EPA’s health standards for five of those pollutants. For the other two — ground-level ozone and fine particulate pollution — Yolo-Solano is considered to be a part of a regional non-attainment area.
Because our air quality does not meet federal standards for ozone or fine particulates, Yolo-Solano AQMD must complete detailed plans to show how those standards will be reached by the EPA’s deadlines.
The California Air Resources Board (ARB) also sets statewide standards for pollutants, including for fouir air pollutants for which there are no federal standards. In addition, for several pollutants the state requires lower concentrations to be considered healthy.