62
2025 (latest)
UNHEALTHY-OR-WORSE AQI DAYS ACROSS TEN METROS
metro-days · 1980–2025 · neither direction is "better" · computed from U.S. EPA AQS annual AQI by CBSA
656
1980
656
high · 1980
38
low · 2019
−91%
since 1980
┊ dashed lines mark 1987 Black Monday crash · 1991 Gulf War recession · 2001 Dot-com bust & 9/11 · 2008 Global financial crisis · 2020 COVID-19 pandemic
Method & caveats. Sum Unhealthy Days + Very Unhealthy Days + Hazardous Days (AQI >150), excluding Unhealthy for Sensitive Groups. Fixed 2020 Census top-ten metro CBSAs: 35620, 31080, 16980, 19100, 26420, 47900, 33100, 37980, 12060, 14460. Sum of reported days, not population-weighted; monitor availability varies. Years missing any metro omitted: none. 2024 PM2.5 AQI breakpoint revision changes category thresholds; fixed ten-metro 2020 Census population ranking; changes in monitoring availability affect counts. Breaks: 2024 PM2.5 AQI breakpoint revision changes category thresholds; fixed ten-metro 2020 Census population ranking; changes in monitoring availability affect counts.
Sources
Every value on this page is read from the publisher below. Current and historical source documents:
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2025.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1980.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1981.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1982.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1983.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1984.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1985.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1986.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1987.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1988.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1989.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1990.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1991.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1992.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1993.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1994.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1995.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1996.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1997.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1998.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_1999.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2000.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2001.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2002.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2003.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2004.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2005.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2006.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2007.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2008.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2009.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2010.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2011.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2012.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2013.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2014.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2015.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2016.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2017.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2018.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2019.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2020.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2021.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2022.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2023.zip
- https://aqs.epa.gov/aqsweb/airdata/annual_aqi_by_cbsa_2024.zip
- https://github.com/danielmiessler/substrate/tree/main/Data/US-Energy-And-Environment
Data
| Year | Unhealthy-or-worse AQI days across ten metros | Change |
|---|---|---|
| 2025 | 62 | −35% |
| 2024 | 96 | +8% |
| 2023 | 89 | +102% |
| 2022 | 44 | −10% |
| 2021 | 49 | −35% |
| 2020 | 75 | +97% |
| 2019 | 38 | −25% |
| 2018 | 51 | −7% |
| 2017 | 55 | +34% |
| 2016 | 41 | −41% |
| 2015 | 70 | +79% |
| 2014 | 39 | −3% |
| 2013 | 40 | −63% |
| 2012 | 107 | −11% |
| 2011 | 120 | +43% |
| 2010 | 84 | +1% |
| 2009 | 83 | −36% |
| 2008 | 130 | −27% |
| 2007 | 178 | −15% |
| 2006 | 210 | −19% |
| 2005 | 258 | +36% |
| 2004 | 190 | −17% |
| 2003 | 229 | −35% |
| 2002 | 350 | +23% |
| 2001 | 284 | +8% |
| 2000 | 263 | −25% |
| 1999 | 351 | −2% |
| 1998 | 358 | +25% |
| 1997 | 286 | +9% |
| 1996 | 262 | −37% |
| 1995 | 414 | +17% |
| 1994 | 355 | −9% |
| 1993 | 388 | +26% |
| 1992 | 308 | −29% |
| 1991 | 435 | +3% |
| 1990 | 422 | +2% |
| 1989 | 414 | −35% |
| 1988 | 638 | +20% |
| 1987 | 531 | +7% |
| 1986 | 496 | −8% |
| 1985 | 541 | +5% |
| 1984 | 515 | −19% |
| 1983 | 634 | +28% |
| 1982 | 495 | −5% |
| 1981 | 521 | −21% |
| 1980 | 656 | — |
Also in Environment & Climate