25. Greenville, South Carolina
> Score: 73.3 (Avg: 65.50)
> Rank in spring of 2019: 24th worst city
> PM2.5 pollution 24-hr average: 57 µg/m3 (EPA’s standard is 35 µg/m3)
> Population: 883,853
24. Columbia, South Carolina
> Score: 74.3 (Avg: 65.50)
> Rank in spring of 2019: 19th worst city
> PM2.5 pollution 24-hr average: 63 µg/m3 (EPA’s standard is 35 µg/m3)
> Population: 816,664
23. Tulsa, Oklahoma
> Score: 75.1 (Avg: 65.50)
> Rank in spring of 2019: 53rd worst city
> PM2.5 pollution 24-hr average: 90 µg/m3 (EPA’s standard is 35 µg/m3)
> Population: 985,233
22. Louisville, Kentucky
> Score: 75.3 (Avg: 65.50)
> Rank in spring of 2019: 6th worst city
> PM2.5 pollution 24-hr average: 126 µg/m3 (EPA’s standard is 35 µg/m3)
> Population: 1,285,270
21. Grand Rapids, Michigan
> Score: 75.6 (Avg: 65.50)
> Rank in spring of 2019: 44th worst city
> PM2.5 pollution 24-hr average: 24 µg/m3 (EPA’s standard is 35 µg/m3)
> Population: 1,050,440