AQMIS (Air Quality and Meteorological Information System) provides real time and historical air quality data.
How to use AQMIS (example):
1. Click the link on the right
2. Select "Air Quality Data"
3. Select either the Daily or Hourly Data tab
4. Select the particulate you wish to view (i.e. PM2.5)
5. Select a date
6. Select the County, Air Basin, or Part of the State
7. Select "Retrieve Data"