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Monitoring Information


Pima County Department of Environmental Quality monitors ambient (outdoor) air pollutants at 17 monitoring stations located throughout eastern Pima County, including the Tucson metropolitan area and Green Valley. There are six principal pollutants, called “criteria” pollutants that are monitored in accordance with the National Ambient Air Quality Standards (NAAQS) set by the Environmental Protection Agency (EPA) to comply with the Federal Clean Air Act. The NAAQS were established to protect public health and the environment from harmful levels of air pollution.


There are six air pollutants monitored by PDEQ which are: carbon monoxide (CO), ozone (O3), particulate matter (PM10 and PM2.5), nitrogen dioxide (NO2), sulfur dioxide (SO2) and lead (Pb).


Map of monitoring locations and information about each site.  Click on the circles to get the site information.  In addition to the sites located on this map, PDEQ operates four other monitoring stations that are not able to be polled electronically.

In addition, PDEQ is conducting a special Beryllium Monitoring Study to determine levels of beryllium in the air surrounding the Materion Ceramics (formally Brush Ceramics) facility in Tucson.


The air quality monitoring section is divided into 3 units; the Field Monitoring unit, the Data Management unit and the Quality Assurance (QA) unit. The field monitoring unit conducts all quality control procedures related to routine operations such as calibrations, equipment checks, troubleshooting and repair of equipment necessary for air quality monitoring. The data management unit handles all operations related to network operations, data acquisition, management, storing and reporting of data. The QA unit operates independently of the field monitoring unit to assure the quality and accuracy of the data recovered.


Almost all routine air quality monitoring data generated by PDEQ are submitted to the U.S. Environmental Protection Agency (EPA) AQS database system. Most air quality monitoring stations in the PDEQ network are equipped with electronic data loggers designed specifically for the logging of air quality data.


The data loggers are programmed to take the electrical outputs from air quality monitoring instruments at a monitoring station and transmit this information via a modem to a central computer data acquisition system (DAS) located in the PDEQ offices. This information is then validated to detect possible erroneous readings, and stored in a central database. The information is then reported to the EPA, documented in summary reports, and made available to local agencies, researchers and the public. 


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