Top 20: US Metro Areas with Worst Ozone Pollution

Notes:
1. Total population represents the at-risk populations for all counties within the respective Combined Metropolitan Statistical Area or Metropolitan Statistical Area.
2. Pediatric asthma estimates are for those under 18 years of age and represent the estimated number of people who had asthma in 2018 based on state rates (BRFSS) applied to population estimates (U.S. Census).
3. Adult asthma estimates are for those 18 years and older and represent the estimated number of people who had asthma in 2018 based on state rates (BRFSS) applied to population estimates (U.S. Census).
4. Adding across rows does not produce valid estimates. Adding the disease categories (asthma, COPD, etc.) will double-count people who have been diagnosed with more than one disease.
5. COPD estimates are for adults 18 and over who have been diagnosed within their lifetime, based on state rates (BRFSS) applied to population estimates (U.S. Census).
6. CV disease is cardiovascular disease and estimates are for adults 18 and over who have been diagnosed within their lifetime, based on state rates (BRFSS) applied to population estimates (U.S. Census).