Air Quality Atlas

The maps show Region 6 air quality levels referenced against the standards set for the six criteria pollutants. The legend for each map, except for the two exceedance day maps, was constructed to show the following information: (1) The blue shade depicts levels less than 10% of the standard; (2) the green shade depicts levels between 10-50% of the standard; (3) the gray shade depicts levels between 50-90% of the standard; (4) the yellow shade depicts levels within 10% of the standard; and (5) the red shade depicts levels over the standard.

Counties not shaded (white) either do not contain monitors, or their monitors did not achieve a data capture rate of at least 75% (exception - all ozone site data were reported). The data used to compose each map were obtained from the EPA's Aerometric Information Retrieval System (AIRS) data base. Analysis of the maps reveals that all Region 6 monitors recorded concentrations below the NAAQS set for lead, nitrogen dioxide, and sulfur dioxide.

Indeed, a significant amount of areas in Region 6 recorded maximum concentrations well below these standards. Additional map analysis shows that one Region 6 county (El Paso) contained monitors recording measurements above the carbon monoxide 8-hour standard, that two Region 6 counties (El Paso and Dona Ana) contained monitors recording measurements above the PM-10 standards, and that every state except Arkansas had at least one monitor with values above the ozone standard.

Following each map displaying the 1996 Region 6 status of particulate and ozone air quality is a map showing the number of days per county in which a monitor recorded concentrations above the PM-10 or ozone standards. [Summary provided by the EPA.]