This GIS dataset contains points which depict air quality monitors within EPA's Air Quality System (AQS) monitoring network. This dataset is updated weekly to reflect the most recent changes in the monitoring network. The monitors are generally operated by State, local, and tribal air pollution control agencies using procedures specified by the U.S. EPA. These agencies collect the data, quality assure it, and then submit it to the EPA Air Quality System (AQS). The GIS dataset includes monitor information and links to download historic air quality data at each monitor.