Table 16

Border Air Quality Information

What kind of data are available?

Summary ambient air quality data are available for criteria pollutants:

• Particulate Matter 10 micrometers or less in diameter (PM10)
• Lead (Pb)
• Sulfur Oxides (SOx) - measured as SO2
• Nitrogen Oxides (NOx) - measured as NO2
• Ozone (O3)
• Carbon Monoxide (CO)

Also, data are provided for a large number of non-criteria pollutants (including Air Toxics). All data are provided through EPA's Aerometric Information Retrieval System (AIRS) and updated quarterly. Only monitors reported in AIRS and located within approximately 100 kilometers (62 miles) of the U.S.-Mexico border are included. State agencies have reviewed the data submitted to AIRS, including the data presented here, to assure data quality.

Are data from monitors in Mexico included?

A significant amount of data from sites in Mexico and along the U.S. border is now available. As per agreement with the Government of Mexico, these data are subject to quality assurance and control measures as the data are processed by Mexico and U.S. border states for entry into AIRS.

What are summary air quality data?

Summary air quality data includes the following data for each monitoring site:

• monitoring site location (address, longitude/latitude, and Universal Transverse Mercator (UTM) system coordinates)
• pollutants monitored
• annual arithmetic and geometric means and standard deviations for hourly (daily for PM10 and Pb) data for each pollutant monitored
• highest and second highest pollutant hourly/daily readings
• pollutant concentration that 95% of the hourly/daily readings are equal to or less than.

Data collected in the last five years for each pollutant at each site are presented. If data for any period within the last five years are not presented, either the site was not in operation during that period or no reliable data are available for that period.