When we look at cities working to make themselves desirable places to live and work, the criteria for Wyse Awards expands beyond financial factors to include quality-of-life factors. In this case, we examined which U.S. cities (combined statistical areas with a population 250k+) have been most effective at improving the quality of the air their residents breathe. Using air quality index (AQI) data sourced from Puraka Clean Air Research, we found the top five cities working the hardest - or possibly the smartest - at decreasing air pollution levels over the last 15 years, with breathtaking results. Compare the results using our interactive chart, available here.
Note - These Wyse Awards are going to cities that have made significant progress in reducing air pollution, not necessarily the same as having the lowest pollution overall. We believe the effects of policy decisions are good indicators of long term city health, so with these awards we want to draw attention to metros that have been able to move the dial on measures impacting quality of life. Learn more about how the EPA measures air quality.
In the last 15 years, Birmingham's median AQI score has gone from 73 to 52 (5 year average). This represents a decrease of 29%, tying Pittsburgh for the 4th greatest reduction nationwide. In response to elevated air pollution levels, Birmingham's Jefferson County implemented an Ozone Alert system that advises residents to avoid activities that contribute to particle pollution - simple steps like waiting until late afternoon to fill up the tank and delaying cutting your grass - during periods of poor air quality.
Metro Size: 1.4m
15-yr AQI Improvement: 29%
The Pittsburgh region, home to 2.6m people, has seen their air quality score improve from a 5-year average of 82 to 58 over the last 15 years, a reduction of 29%, tying Birmingham as the fourth best improvement nationally among metro regions with 250k or more people. While a median AQI score of 58 still exceeds Allegheny County Health Department goals, it shows that a long-term effort to curb pollutants via a combination of enforcement and incentives for local residents and business is yielding results
Metro Size: 2.6m
15-yr AQI Improvement: 29%
The Tri-Cities region of Kingsport, Bristol and Johnson city, home to over half a million people, has seen the third-largest reduction in particulate pollution out of any metro area in the country during the last fifteen years. From 2004 to 2009, this area's median AQI score averaged 70.4, well above levels considered "good" by the U.S. Environmental Protection Agency. During the five-year period from 2014-2018, actions by the (now-defunct) Ozone Action Partnership as well as the East Tennessee Clean Fuel Coalition have succeeded in bringing the median level down to 46.4, within the "good" range. This represents an impressive reduction in particulate pollution of more than 34%.
Metro Size: 509k
15-yr AQI Improvement: 34%
Home to almost 3 million people, the St. Louis area has seen air pollution levels drop more than almost any other metro area in the country over the past 15 years. That being said, the median AQI of 53.6 for the five-year period from 2014-2018 was still above levels considered "good". A stronger, more strategic St. Louis County Air Pollution Control Program could potentially do even more to make the air quality breathable for all residents of this midwest region, but credit is certainly deserved for bringing the levels down significantly over the last decade and a half.
Metro Size: 2.9m
15-yr AQI Improvement: 38%
The residents of Knox County receive Wyse Gold for a valiant effort to reduce air pollution from a median score of 82 to a score of 47 over the past 15 years. A series of specific goals and educational campaigns by an assertive Air Quality Management Division deserves credit for helping to reduce particle pollution (like pm 2.5) by almost 43% from 2004 to 2018, the largest decrease in the country for metros with a population of 250k or more. Congratulations to this region for setting smart goals, and following through on its commitment to helping its residents achieve continuous access to clean, healthy air.
Metro Size: 1.1m
15-yr AQI Improvement: 43%