Title,Code,"Demographic Group",Population,Period,Estimate,Unit,"Lower CI","Upper CI",SE,Locality "Reduce the number of days people are exposed to unhealthy air - EH-01",EH-01,Total,Total,2016-18,"4,295,962,018","AQI-weighted people days",,,,"United States" "Reduce the number of days people are exposed to unhealthy air - EH-01",EH-01,Total,Total,2019-21,"4,534,737,587","AQI-weighted people days",,,,"United States" Footnotes "DSU: Data do not meet the criteria for statistical reliability, data quality, or confidentiality." "DNA: Data have not been analyzed." "DNC: Data for specific population not collected." "--- : Data are not available." "Data Source" "Air Quality System (AQS)"