Obtaining AQS Data
The purpose of this web page is to assist those who want to obtain files of the very detailed ambient air quality data (e.g., hourly measurements) from AQS for analysis.
NOTE: If you are interested in only summary information (e.g., daily or yearly means, or peak concentrations), it is available elsewhere. Summary data are accessible to the public from the AirData and the AIRNOW web area. Unless you are doing detailed analysis of the data, summary data will likely meet your needs. If you are interested in county level air quality index (AQI) information, it is available here. (AQI index)
AQS data is available from various places, depending on the data you need. Registered users of the AQS application may download data from the production database via standard reports or ad hoc query tools.
In addition to the above methods, a table of about 270 files of detailed data (i.e., the collected sample values reported to AQS on hourly, daily, or other time-related bases) are available from links in the table of files below. These national files include a year's worth of data for CO, PB, NO2, O3, PAMS VOC, PM2.5, PM Fine Speciation, PM10, NOY, NOX, or SO2 for 1993 through last year, plus data available through the date the file was created for this year. Data older than these data in this table or for other parameters may be requested by clicking on "Contact Us" and sending an email request to Michael Hamlin.
The AQS Data Mart is available for public access to AQS data from 1980 to present. If the detailed data you need is not available in the table of yearly data files, please use the AQS Data Mart. Instructions for accessing the AQS Data Mart are available there.
Non-registered users may also request detailed data files from tribal, state, or local agencies directly, or from EPA regional or headquarters offices. These agencies may be located through the "User Support and Agency Contacts" link on the sidebar to the left on this page.