The AQI is an index for reporting daily air quality. It tells you how clean or polluted your air is, and what associated health concerns you should be aware of. The AQI focuses on health effects that can happen within a few hours or days after breathing polluted air. EPA uses the AQI for five major air pollutants regulated by the Clean Air Act: ground-level ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide. For each of these pollutants, EPA has established national air quality standards to protect against harmful health. (EPA-454K-03-002, August 2003, http://www.airnow.gov/)

• Action Day Program
• Forecast
• Real-time Ozone Data Program
• Today's AQI Forecast
• A Guide to Air Quality and Your Health
• EPA AirNow
• What You Can Do

• Mountain View Air Quality
• Menlo Park Air Quality
• Fremont Air Quality
• San Carlos Air Quality
• Palo Alto Air Quality
• Half Moon Bay Air Quality
• San Mateo Air Quality
• Sunnyvale Air Quality
• Redwood City Air Quality
• Newark Air Quality