Geographic Area (Select One)
Air Pollutant (Select One)
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These maps illustrate the modeled ambient concentration of air toxics by county in 1999. Map colors indicate ranges of median concentration values, and each county is colored according to its value relative to the rest of the U.S. Pollutant concentration is expressed in micrograms per cubic meter of air (µg/m3).
If most counties have the same pollutant concentration value (e.g.,
for coke oven emissions), most of the map is shaded white. For some
pollutants (e.g., ethylene dibromide, ethylene dichloride, carbon
tetrachloride, and PCBs), the range of concentration values is very
small. Therefore, variation in color for these maps represent relatively small changes in concentration.