Ozone is one of the five major air pollutants regulated by the Clean Air Act.  The U.S. EPA calculates the Air Quality Index (AQI) for ozone. The AQI is an index for reporting daily air quality. It tells you how clean or polluted your air is, and what associated health effects might be a concern for you. The higher the AQI value, the greater the level of air pollution and the greater the health concern are. Click here to lean more about the Air Quality Index (AQI).

You can check http://www.epa.gov/airnow/ for AQI nationwide. Choose the State of California and you will find information for various locations in California. Or you can get such information directly from your local Air Quality Management Districts (AQMDs), such as South Coast Air Quality Management District and Bay Area Air Quality Management District.  The latest ozone summary data and real-time hourly ozone values (Click here) for locations in California can also be found from Air Quality and Meteorological Information System (AQMIS) website maintained by the California Air Resources Board (CARB).