This measure, based on data from the Environmental Protection Agency, evaluates states on the number of days the Air Quality Index in counties was not rated “good.” U.S. News calculated a ...

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The US government will stop sharing air quality data gathered from its embassies and consulates, worrying local scientists and experts who say the effort was vital to monitor global air quality ...

It comprises two measures: the number of days with an air quality index below a certain threshold and the number of violation points against drinking water systems in each state. Learn more about ...