AirNow on Google Earth from the EPA

Users of Google Earth now have access to the latest air quality data from the EPA. EPA’s scientific air quality information in real time is now available on Google Earth. This information tool accesses the AIRNow database hourly so that the Air Quality Index (AQI) displays the most current air quality conditions. Public health officials, media outlets and the general public can now view timely air quality information, by city, on Google Earth. See more at http://airnow.gov/ - grab the KML here