Air pollution is a grave problem in America. A “State of the Air” report is generate annually. This is an assessment of the current pollution levels which are gathered from monitoring of air quality by federal, tribal, state and county agencies.
The data is collected from the U.S. Environmental Protection Agency, specifically from their Air Quality System database. Data is gathered from select monitoring sites.
The methodology includes a collection of ozone concentrations and quality over a three-year period, short-term particle pollution data analysis and an Air quality index assigning pollution levels in accordance with parts per billion and an average for specified days.
Grades are assigned over a 24 hour period and this is used to determine pollution levels when the factors are weighted numerically, then multiplied with the total number of days in each category, and finally summed up for the annual total over a three-year period.
This is how the county grades for air quality with regard to ozone levels. The measurements are used to determine the health risk for populations living in each respective county or metropolitan area monitored. Air quality is determined by Ozone, year round pollution and short-term particle pollution.
With this in mind, here are the 25 most polluted cities in the United States.