EnviroNearby

Hamilton County, Tennessee air quality history

Daily Air Quality Index summaries from EPA monitors in Hamilton, Tennessee, 1980–2025.

65%
Good days in 2025
44
Median daily AQI, 2025
2
Days above 100 in 2025
365
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Hamilton, Tennessee on 365 days. 237 of those days (65%) were in the Good range, and the median daily AQI was 44. That median is higher than the typical monitored county in Tennessee (median 39 across 23 counties), and higher than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 240 days. Across the years with fuller monitoring, the share of Good days fell: an average of 66% in 1980–1982 versus 56% in 2023–2025.

How the days broke down each year

Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.

Share of monitored days in each AQI category, by year0%25%50%75%100%1980: Good 224 of 360 days1980: Moderate 69 of 360 days1980: Unhealthy for Sensitive Groups 50 of 360 days1980: Unhealthy 14 of 360 days1980: Very Unhealthy 3 of 360 days19801981: Good 249 of 361 days1981: Moderate 66 of 361 days1981: Unhealthy for Sensitive Groups 33 of 361 days1981: Unhealthy 11 of 361 days1981: Very Unhealthy 2 of 361 days1982: Good 242 of 361 days1982: Moderate 77 of 361 days1982: Unhealthy for Sensitive Groups 35 of 361 days1982: Unhealthy 6 of 361 days1982: Very Unhealthy 1 of 361 days1983: Good 230 of 365 days1983: Moderate 68 of 365 days1983: Unhealthy for Sensitive Groups 49 of 365 days1983: Unhealthy 15 of 365 days1983: Very Unhealthy 2 of 365 days1983: Hazardous 1 of 365 days1984: Good 262 of 366 days1984: Moderate 66 of 366 days1984: Unhealthy for Sensitive Groups 32 of 366 days1984: Unhealthy 6 of 366 days1985: Good 260 of 365 days1985: Moderate 78 of 365 days1985: Unhealthy for Sensitive Groups 22 of 365 days1985: Unhealthy 5 of 365 days19851986: Good 162 of 275 days1986: Moderate 74 of 275 days1986: Unhealthy for Sensitive Groups 29 of 275 days1986: Unhealthy 9 of 275 days1986: Very Unhealthy 1 of 275 days1987: Good 216 of 365 days1987: Moderate 90 of 365 days1987: Unhealthy for Sensitive Groups 41 of 365 days1987: Unhealthy 17 of 365 days1987: Very Unhealthy 1 of 365 days1988: Good 232 of 366 days1988: Moderate 66 of 366 days1988: Unhealthy for Sensitive Groups 44 of 366 days1988: Unhealthy 21 of 366 days1988: Very Unhealthy 3 of 366 days1989: Good 219 of 308 days1989: Moderate 63 of 308 days1989: Unhealthy for Sensitive Groups 22 of 308 days1989: Unhealthy 4 of 308 days1990: Good 152 of 290 days1990: Moderate 82 of 290 days1990: Unhealthy for Sensitive Groups 43 of 290 days1990: Unhealthy 13 of 290 days19901991: Good 237 of 337 days1991: Moderate 77 of 337 days1991: Unhealthy for Sensitive Groups 22 of 337 days1991: Unhealthy 1 of 337 days1992: Good 288 of 364 days1992: Moderate 56 of 364 days1992: Unhealthy for Sensitive Groups 19 of 364 days1992: Unhealthy 1 of 364 days1993: Good 239 of 365 days1993: Moderate 79 of 365 days1993: Unhealthy for Sensitive Groups 37 of 365 days1993: Unhealthy 10 of 365 days1994: Good 262 of 365 days1994: Moderate 82 of 365 days1994: Unhealthy for Sensitive Groups 15 of 365 days1994: Unhealthy 5 of 365 days1994: Very Unhealthy 1 of 365 days1995: Good 250 of 365 days1995: Moderate 77 of 365 days1995: Unhealthy for Sensitive Groups 30 of 365 days1995: Unhealthy 7 of 365 days1995: Very Unhealthy 1 of 365 days19951996: Good 243 of 366 days1996: Moderate 81 of 366 days1996: Unhealthy for Sensitive Groups 34 of 366 days1996: Unhealthy 8 of 366 days1997: Good 200 of 315 days1997: Moderate 71 of 315 days1997: Unhealthy for Sensitive Groups 36 of 315 days1997: Unhealthy 8 of 315 days1998: Good 103 of 240 days1998: Moderate 76 of 240 days1998: Unhealthy for Sensitive Groups 33 of 240 days1998: Unhealthy 23 of 240 days1998: Very Unhealthy 5 of 240 days1999: Good 90 of 287 days1999: Moderate 139 of 287 days1999: Unhealthy for Sensitive Groups 43 of 287 days1999: Unhealthy 13 of 287 days1999: Very Unhealthy 2 of 287 days2000: Good 102 of 289 days2000: Moderate 136 of 289 days2000: Unhealthy for Sensitive Groups 40 of 289 days2000: Unhealthy 9 of 289 days2000: Very Unhealthy 2 of 289 days20002001: Good 116 of 291 days2001: Moderate 143 of 291 days2001: Unhealthy for Sensitive Groups 28 of 291 days2001: Unhealthy 4 of 291 days2002: Good 113 of 287 days2002: Moderate 126 of 287 days2002: Unhealthy for Sensitive Groups 32 of 287 days2002: Unhealthy 14 of 287 days2002: Very Unhealthy 2 of 287 days2003: Good 119 of 286 days2003: Moderate 147 of 286 days2003: Unhealthy for Sensitive Groups 16 of 286 days2003: Unhealthy 4 of 286 days2004: Good 125 of 286 days2004: Moderate 147 of 286 days2004: Unhealthy for Sensitive Groups 13 of 286 days2004: Unhealthy 1 of 286 days2005: Good 115 of 286 days2005: Moderate 143 of 286 days2005: Unhealthy for Sensitive Groups 26 of 286 days2005: Unhealthy 2 of 286 days20052006: Good 109 of 292 days2006: Moderate 152 of 292 days2006: Unhealthy for Sensitive Groups 27 of 292 days2006: Unhealthy 4 of 292 days2007: Good 64 of 361 days2007: Moderate 243 of 361 days2007: Unhealthy for Sensitive Groups 50 of 361 days2007: Unhealthy 4 of 361 days2008: Good 107 of 366 days2008: Moderate 243 of 366 days2008: Unhealthy for Sensitive Groups 15 of 366 days2008: Unhealthy 1 of 366 days2009: Good 142 of 363 days2009: Moderate 218 of 363 days2009: Unhealthy for Sensitive Groups 3 of 363 days2010: Good 136 of 301 days2010: Moderate 145 of 301 days2010: Unhealthy for Sensitive Groups 19 of 301 days2010: Unhealthy 1 of 301 days20102011: Good 145 of 300 days2011: Moderate 145 of 300 days2011: Unhealthy for Sensitive Groups 10 of 300 days2012: Good 148 of 285 days2012: Moderate 127 of 285 days2012: Unhealthy for Sensitive Groups 8 of 285 days2012: Unhealthy 2 of 285 days2013: Good 200 of 288 days2013: Moderate 87 of 288 days2013: Unhealthy for Sensitive Groups 1 of 288 days2014: Good 193 of 287 days2014: Moderate 93 of 287 days2014: Unhealthy for Sensitive Groups 1 of 287 days2015: Good 211 of 284 days2015: Moderate 70 of 284 days2015: Unhealthy for Sensitive Groups 3 of 284 days20152016: Good 179 of 288 days2016: Moderate 106 of 288 days2016: Unhealthy for Sensitive Groups 2 of 288 days2016: Unhealthy 1 of 288 days2017: Good 156 of 338 days2017: Moderate 180 of 338 days2017: Unhealthy for Sensitive Groups 2 of 338 days2018: Good 193 of 365 days2018: Moderate 171 of 365 days2018: Unhealthy for Sensitive Groups 1 of 365 days2019: Good 181 of 365 days2019: Moderate 184 of 365 days2020: Good 219 of 364 days2020: Moderate 144 of 364 days2020: Unhealthy 1 of 364 days20202021: Good 191 of 351 days2021: Moderate 159 of 351 days2021: Unhealthy for Sensitive Groups 1 of 351 days2022: Good 169 of 341 days2022: Moderate 171 of 341 days2022: Unhealthy for Sensitive Groups 1 of 341 days2023: Good 175 of 365 days2023: Moderate 187 of 365 days2023: Unhealthy for Sensitive Groups 3 of 365 days2024: Good 190 of 349 days2024: Moderate 156 of 349 days2024: Unhealthy for Sensitive Groups 3 of 349 days2025: Good 237 of 365 days2025: Moderate 126 of 365 days2025: Unhealthy for Sensitive Groups 2 of 365 days2025
  • Good
  • Moderate
  • Unhealthy for Sensitive Groups
  • Unhealthy
  • Very Unhealthy
  • Hazardous

Typical and high-end AQI over time

The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.

Median and 90th-percentile daily AQI, by year0501001502001980: 90th percentile AQI 1291981: 90th percentile AQI 1121982: 90th percentile AQI 1081983: 90th percentile AQI 1261984: 90th percentile AQI 1011985: 90th percentile AQI 931986: 90th percentile AQI 1151987: 90th percentile AQI 1221988: 90th percentile AQI 1331989: 90th percentile AQI 931990: 90th percentile AQI 1261991: 90th percentile AQI 841992: 90th percentile AQI 771993: 90th percentile AQI 1081994: 90th percentile AQI 901995: 90th percentile AQI 1011996: 90th percentile AQI 1051997: 90th percentile AQI 1151998: 90th percentile AQI 1591999: 90th percentile AQI 1262000: 90th percentile AQI 1222001: 90th percentile AQI 1052002: 90th percentile AQI 1362003: 90th percentile AQI 932004: 90th percentile AQI 902005: 90th percentile AQI 1002006: 90th percentile AQI 1012007: 90th percentile AQI 1082008: 90th percentile AQI 842009: 90th percentile AQI 712010: 90th percentile AQI 902011: 90th percentile AQI 802012: 90th percentile AQI 802013: 90th percentile AQI 612014: 90th percentile AQI 652015: 90th percentile AQI 622016: 90th percentile AQI 672017: 90th percentile AQI 672018: 90th percentile AQI 652019: 90th percentile AQI 672020: 90th percentile AQI 612021: 90th percentile AQI 642022: 90th percentile AQI 662023: 90th percentile AQI 712024: 90th percentile AQI 632025: 90th percentile AQI 611980: Median AQI 431981: Median AQI 401982: Median AQI 411983: Median AQI 431984: Median AQI 401985: Median AQI 401986: Median AQI 471987: Median AQI 461988: Median AQI 431989: Median AQI 421990: Median AQI 491991: Median AQI 421992: Median AQI 371993: Median AQI 411994: Median AQI 391995: Median AQI 401996: Median AQI 421997: Median AQI 451998: Median AQI 581999: Median AQI 642000: Median AQI 612001: Median AQI 572002: Median AQI 592003: Median AQI 552004: Median AQI 542005: Median AQI 562006: Median AQI 582007: Median AQI 642008: Median AQI 582009: Median AQI 542010: Median AQI 522011: Median AQI 512012: Median AQI 502013: Median AQI 452014: Median AQI 442015: Median AQI 432016: Median AQI 472017: Median AQI 512018: Median AQI 482019: Median AQI 512020: Median AQI 462021: Median AQI 482022: Median AQI 512023: Median AQI 512024: Median AQI 482025: Median AQI 441980198519901995200020052010201520202025
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2025

On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.

PollutantDays as main pollutantShare of monitored days
Fine particles (PM2.5)24066%
Ozone12534%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
202536523712620004461141PM2.5
202434919015630004863126PM2.5
202336517518730005171137PM2.5
202234116917110005166105PM2.5
202135119115910004864101PM2.5
202036421914401004661151PM2.5
20193651811840000516797PM2.5
201836519317110004865101PM2.5
201733815618020005167108PM2.5
201628817910621004767186Ozone
20152842117030004362133Ozone
20142871939310004465105Ozone
20132882008710004561101Ozone
201228514812782005080161Ozone
2011300145145100005180129Ozone
2010301136145191005290159Ozone
200936314221830005471136PM2.5
2008366107243151005884182PM2.5
2007361642435040064108195PM2.5
20062921091522740058101169Ozone
20052861151432620056100185Ozone
2004286125147131005490200Ozone
2003286119147164005593195Ozone
200228711312632142059136207Ozone
20012911161432840057105185Ozone
20002891021364092061122205Ozone
19992879013943132064126203Ozone
19982401037633235058159213Ozone
1997315200713680045115169Ozone
1996366243813480042105195Ozone
1995365250773071040101202Ozone
199436526282155103990201Ozone
19933652397937100041108182Ozone
199236428856191003777156Ozone
199133723777221004284154Ozone
19902901528243130049126195Ozone
198930821963224004293182Ozone
19883662326644213043133210Ozone
19873652169041171046122205Ozone
1986275162742991047115204Ozone
198536526078225004093177Ozone
1984366262663260040101177Ozone
19833652306849152143126346Ozone
1982361242773561041108205Ozone
19813612496633112040112218Ozone
19803602246950143043129208Ozone

What this data can and can’t tell you

It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.

It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.

Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.

Counties in Tennessee with a similar median AQI in 2025

All monitored counties in Tennessee

Source: U.S. EPA AirData, “Annual AQI by County” files for 1980–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem