Inequity Identification Tool (IIT) Air Cost by County

This file contains the US county polygons with estimates of the air pollution cost from roads within that county, population counts for different demographics, estimates of how much air pollution cost from roads each demographic is absorbing, and the air-equity ratio for each demographic--the percent of air pollution cost borne divided by the percent of population within the county. The cost of air pollution is estimated in a separate shapefile and the results are aggregated together through FHWA's Inequity Identification Tool (IIT). For more information on this data please visit: https://maps.dot.gov/fhwa/iit/