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Border Air Quality Data

What Kind of Data Are Available?

This Web site has air quality data for criteria and hazardous air pollutants.

Criteria air pollutants are airborne substances for which the United States and Mexico have established health-based exposure limits. In the U.S., EPA sets limits called national ambient air quality standards. In Mexico, the Secretaria del Medio Ambiente Recursos Naturales (SEMARNAT) sets limits called Normas Ambientales para Aire.

The criteria air pollutants are:

Nitrogen dioxide and sulfur dioxide each serve as indicators of the concentrations of several chemically similar compounds, nitrogen oxides (NOx) and sulfur oxides (SOx). Lead is a component of particulate matter.

Hazardous air pollutants (HAPs) are substances that are known or suspected to cause serious health problems. Section 112(b) of the U.S. Clean Air Act identifies a list of 188 pollutants as HAPs. Some of those are further subdivided for air monitoring procedures, resulting in about 200 HAPs that may be monitored for their ambient concentrations in air. In practice, air monitoring is done for about one-third of the HAPs.

Other Sources of Border Air Quality Data

EPA's AIRNOW Web site provides links to real-time ozone air pollution data and ozone forecasts for all U.S. states along the border, as well as ozone data for other non-border states.   

Are Data From Monitors in Mexico Included?

A significant amount of data from sites in Mexico and along the U.S. border is 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 EPA's air quality database, AQS.

What Are Standard-Relevant Air Quality Data?

Standard-relevant air quality data are the particular values used in determining whether an area is attaining national air quality standards for each criteria pollutant, plus descriptive information about monitoring sites. The air quality standards are defined to protect the health of people working or playing outdoors. For most pollutants, there is a standard for short-term exposure and another standard for longer-term exposure. Measured air pollutant concentrations are averaged over the time intervals of the applicable standards, and compared with the value of the standards.

Click on the link to see a table containing the current U.S. National Ambient Air Quality Standards

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