California Air Quality

Air quality provides the public with information about the reporting areas. The reporting areas vary according to size and population, ranging from neighborhood to entire county. Generally, air quality observations are updated once per hour and forecasts are generated once a day. Forecasts for each reporting area are unique and not necessarily available for all reporting areas. Forecasts may not be daily or seasonal, such as winter or summer, or may range from one to six days. In some cases, forecasts can only refer to pollutants (eg ozone, PM2.5).