This section contains selected PM animations that show how PM patterns change over the course of a given day - as a map of the Bay Area changes color according to the Air Quality Index scale.
Although the Bay Area is one of the cleanest of the five major urban air basins in California, there are still several days annually when air pollution exceeds the state or federal air quality standards.
The links below depict daily particulate matter (PM) development patterns in the region. They show how PM patterns change over the course of a given day - as a map of the Bay Area changes color according to the Air Quality Index (or AQI) scale as pollution concentrations increase and subside.
Today’s Current Hour Still Image
Yesterday's Average (PM 2.5 only)
Note: Yesterday’s maps are not available until around 9am the following morning.
Air District systems will undergo planned maintenance from 8am Friday 4/28 through 11pm Sunday 4/30.
There may be disruptions in some services. We apologize for any inconvenience.
Air Quality Index
PM Health Effects