Air Quality

Since the population and most pollution sources are concentrated in the western portion of San Diego County, the District conducts most of its air sampling at monitoring sites in the western region. Data collected from the monitoring stations is used to assess the County's air quality attainment status and to forecast air pollution levels.

The United States Environmental Protection Agency (EPA) has updated the Air Quality Index (AQI).

Updates to the AQI include:

• New scale reflects PM2.5 standard changes from 12 to 9.0 micrograms per cubic meter (µg/ m3) to reflect public health findings.
• Changes reflect a February 7, 2024, rule to strengthen National Ambient Air Quality Standards (NAAQS) for fine particle pollution.
• Changes to the AQI are effective May 6, 2024.

The updates by the EPA come after learning more about the health impacts of breathing air containing particle pollution. While the air quality around San Diego County has not changed, there will be days where the air quality is forecasted under moderate conditions as part of the PM2.5 standards.

Read our Facts Here

AQI Map

EPA AirNow for San Diego