EnviroNearby

Allen County, Indiana air quality history

Daily Air Quality Index summaries from EPA monitors in Allen, Indiana, 1980–2025.

60%
Good days in 2025
44
Median daily AQI, 2025
3
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 Allen, Indiana on 365 days. 219 of those days (60%) were in the Good range, and the median daily AQI was 44. That median is higher than the typical monitored county in Indiana (median 41 across 33 counties), and higher than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 190 days. Across the years with fuller monitoring, the share of Good days fell: an average of 76% in 1980–1982 versus 66% 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 262 of 357 days1980: Moderate 46 of 357 days1980: Unhealthy for Sensitive Groups 29 of 357 days1980: Unhealthy 18 of 357 days1980: Very Unhealthy 2 of 357 days19801981: Good 284 of 363 days1981: Moderate 45 of 363 days1981: Unhealthy for Sensitive Groups 24 of 363 days1981: Unhealthy 9 of 363 days1981: Very Unhealthy 1 of 363 days1982: Good 275 of 357 days1982: Moderate 48 of 357 days1982: Unhealthy for Sensitive Groups 25 of 357 days1982: Unhealthy 9 of 357 days1983: Good 241 of 363 days1983: Moderate 58 of 363 days1983: Unhealthy for Sensitive Groups 36 of 363 days1983: Unhealthy 25 of 363 days1983: Very Unhealthy 3 of 363 days1984: Good 261 of 342 days1984: Moderate 45 of 342 days1984: Unhealthy for Sensitive Groups 29 of 342 days1984: Unhealthy 7 of 342 days1985: Good 128 of 220 days1985: Moderate 67 of 220 days1985: Unhealthy for Sensitive Groups 19 of 220 days1985: Unhealthy 6 of 220 days19851986: Good 212 of 289 days1986: Moderate 56 of 289 days1986: Unhealthy for Sensitive Groups 20 of 289 days1986: Unhealthy 1 of 289 days1987: Good 271 of 365 days1987: Moderate 60 of 365 days1987: Unhealthy for Sensitive Groups 30 of 365 days1987: Unhealthy 4 of 365 days1988: Good 234 of 366 days1988: Moderate 85 of 366 days1988: Unhealthy for Sensitive Groups 23 of 366 days1988: Unhealthy 19 of 366 days1988: Very Unhealthy 5 of 366 days1989: Good 269 of 365 days1989: Moderate 69 of 365 days1989: Unhealthy for Sensitive Groups 21 of 365 days1989: Unhealthy 5 of 365 days1989: Very Unhealthy 1 of 365 days1990: Good 291 of 365 days1990: Moderate 53 of 365 days1990: Unhealthy for Sensitive Groups 20 of 365 days1990: Unhealthy 1 of 365 days19901991: Good 272 of 365 days1991: Moderate 65 of 365 days1991: Unhealthy for Sensitive Groups 23 of 365 days1991: Unhealthy 5 of 365 days1992: Good 294 of 366 days1992: Moderate 53 of 366 days1992: Unhealthy for Sensitive Groups 13 of 366 days1992: Unhealthy 6 of 366 days1993: Good 288 of 365 days1993: Moderate 58 of 365 days1993: Unhealthy for Sensitive Groups 17 of 365 days1993: Unhealthy 2 of 365 days1994: Good 229 of 328 days1994: Moderate 53 of 328 days1994: Unhealthy for Sensitive Groups 33 of 328 days1994: Unhealthy 12 of 328 days1994: Very Unhealthy 1 of 328 days1995: Good 262 of 362 days1995: Moderate 64 of 362 days1995: Unhealthy for Sensitive Groups 25 of 362 days1995: Unhealthy 11 of 362 days19951996: Good 272 of 366 days1996: Moderate 61 of 366 days1996: Unhealthy for Sensitive Groups 24 of 366 days1996: Unhealthy 9 of 366 days1997: Good 299 of 365 days1997: Moderate 44 of 365 days1997: Unhealthy for Sensitive Groups 15 of 365 days1997: Unhealthy 7 of 365 days1998: Good 240 of 352 days1998: Moderate 77 of 352 days1998: Unhealthy for Sensitive Groups 28 of 352 days1998: Unhealthy 7 of 352 days1999: Good 225 of 357 days1999: Moderate 95 of 357 days1999: Unhealthy for Sensitive Groups 26 of 357 days1999: Unhealthy 11 of 357 days2000: Good 220 of 364 days2000: Moderate 128 of 364 days2000: Unhealthy for Sensitive Groups 12 of 364 days2000: Unhealthy 4 of 364 days20002001: Good 227 of 365 days2001: Moderate 118 of 365 days2001: Unhealthy for Sensitive Groups 18 of 365 days2001: Unhealthy 2 of 365 days2002: Good 117 of 365 days2002: Moderate 213 of 365 days2002: Unhealthy for Sensitive Groups 21 of 365 days2002: Unhealthy 14 of 365 days2003: Good 133 of 365 days2003: Moderate 214 of 365 days2003: Unhealthy for Sensitive Groups 13 of 365 days2003: Unhealthy 5 of 365 days2004: Good 208 of 366 days2004: Moderate 152 of 366 days2004: Unhealthy for Sensitive Groups 6 of 366 days2005: Good 102 of 365 days2005: Moderate 226 of 365 days2005: Unhealthy for Sensitive Groups 32 of 365 days2005: Unhealthy 5 of 365 days20052006: Good 136 of 365 days2006: Moderate 220 of 365 days2006: Unhealthy for Sensitive Groups 9 of 365 days2007: Good 100 of 365 days2007: Moderate 245 of 365 days2007: Unhealthy for Sensitive Groups 19 of 365 days2007: Unhealthy 1 of 365 days2008: Good 88 of 362 days2008: Moderate 268 of 362 days2008: Unhealthy for Sensitive Groups 6 of 362 days2009: Good 79 of 365 days2009: Moderate 283 of 365 days2009: Unhealthy for Sensitive Groups 3 of 365 days2010: Good 78 of 365 days2010: Moderate 279 of 365 days2010: Unhealthy for Sensitive Groups 8 of 365 days20102011: Good 132 of 361 days2011: Moderate 221 of 361 days2011: Unhealthy for Sensitive Groups 8 of 361 days2012: Good 91 of 362 days2012: Moderate 255 of 362 days2012: Unhealthy for Sensitive Groups 15 of 362 days2012: Unhealthy 1 of 362 days2013: Good 170 of 365 days2013: Moderate 195 of 365 days2014: Good 112 of 359 days2014: Moderate 241 of 359 days2014: Unhealthy for Sensitive Groups 6 of 359 days2015: Good 177 of 357 days2015: Moderate 178 of 357 days2015: Unhealthy for Sensitive Groups 1 of 357 days2015: Unhealthy 1 of 357 days20152016: Good 194 of 358 days2016: Moderate 161 of 358 days2016: Unhealthy for Sensitive Groups 3 of 358 days2017: Good 214 of 365 days2017: Moderate 150 of 365 days2017: Unhealthy for Sensitive Groups 1 of 365 days2018: Good 193 of 365 days2018: Moderate 166 of 365 days2018: Unhealthy for Sensitive Groups 6 of 365 days2019: Good 200 of 365 days2019: Moderate 164 of 365 days2019: Unhealthy for Sensitive Groups 1 of 365 days2020: Good 232 of 366 days2020: Moderate 132 of 366 days2020: Unhealthy for Sensitive Groups 2 of 366 days20202021: Good 257 of 365 days2021: Moderate 108 of 365 days2022: Good 326 of 351 days2022: Moderate 23 of 351 days2022: Unhealthy for Sensitive Groups 2 of 351 days2023: Good 267 of 361 days2023: Moderate 89 of 361 days2023: Unhealthy for Sensitive Groups 5 of 361 days2024: Good 229 of 366 days2024: Moderate 137 of 366 days2025: Good 219 of 365 days2025: Moderate 143 of 365 days2025: Unhealthy for Sensitive Groups 3 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 year0501001501980: 90th percentile AQI 1221981: 90th percentile AQI 1001982: 90th percentile AQI 931983: 90th percentile AQI 1431984: 90th percentile AQI 1011985: 90th percentile AQI 1081986: 90th percentile AQI 871987: 90th percentile AQI 1001988: 90th percentile AQI 1221989: 90th percentile AQI 901990: 90th percentile AQI 771991: 90th percentile AQI 931992: 90th percentile AQI 711993: 90th percentile AQI 771994: 90th percentile AQI 1191995: 90th percentile AQI 1001996: 90th percentile AQI 971997: 90th percentile AQI 781998: 90th percentile AQI 1001999: 90th percentile AQI 1012000: 90th percentile AQI 852001: 90th percentile AQI 902002: 90th percentile AQI 972003: 90th percentile AQI 872004: 90th percentile AQI 772005: 90th percentile AQI 1012006: 90th percentile AQI 752007: 90th percentile AQI 902008: 90th percentile AQI 812009: 90th percentile AQI 822010: 90th percentile AQI 842011: 90th percentile AQI 772012: 90th percentile AQI 842013: 90th percentile AQI 662014: 90th percentile AQI 772015: 90th percentile AQI 692016: 90th percentile AQI 672017: 90th percentile AQI 632018: 90th percentile AQI 682019: 90th percentile AQI 642020: 90th percentile AQI 612021: 90th percentile AQI 632022: 90th percentile AQI 482023: 90th percentile AQI 642024: 90th percentile AQI 642025: 90th percentile AQI 691980: Median AQI 371981: Median AQI 311982: Median AQI 381983: Median AQI 381984: Median AQI 341985: Median AQI 471986: Median AQI 411987: Median AQI 381988: Median AQI 451989: Median AQI 401990: Median AQI 391991: Median AQI 371992: Median AQI 341993: Median AQI 351994: Median AQI 381995: Median AQI 321996: Median AQI 281997: Median AQI 291998: Median AQI 331999: Median AQI 422000: Median AQI 442001: Median AQI 432002: Median AQI 552003: Median AQI 542004: Median AQI 462005: Median AQI 582006: Median AQI 542007: Median AQI 582008: Median AQI 592009: Median AQI 632010: Median AQI 612011: Median AQI 552012: Median AQI 602013: Median AQI 522014: Median AQI 552015: Median AQI 512016: Median AQI 482017: Median AQI 472018: Median AQI 502019: Median AQI 492020: Median AQI 452021: Median AQI 402022: Median AQI 352023: Median AQI 422024: Median AQI 452025: 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)19052%
Ozone17548%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
202536521914330004469115PM2.5
202436622913700004564100Ozone
20233612678950004264129Ozone
20223513262320003548115Ozone
202136525710800004063100Ozone
202036623213220004561120PM2.5
201936520016410004964101PM2.5
201836519316660005068122PM2.5
201736521415010004763105PM2.5
201635819416130004867119PM2.5
201535717717811005169176PM2.5
201435911224160005577147PM2.5
20133651701950000526697PM2.5
201236291255151006084179PM2.5
201136113222180005577122PM2.5
20103657827980006184121PM2.5
20093657928330006382121PM2.5
20083628826860005981120PM2.5
2007365100245191005890151PM2.5
200636513622090005475126PM2.5
20053651022263250058101164PM2.5
200436620815260004677147PM2.5
2003365133214135005487197PM2.5
20023651172132114005597187PM2.5
2001365227118182004390169Ozone
2000364220128124004485182Ozone
19993572259526110042101172Ozone
1998352240772870033100177Ozone
199736529944157002978161Ozone
199636627261249002897179Ozone
19953622626425110032100197Ozone
19943282295333121038119202Ozone
199336528858172003577182Ozone
199236629453136003471197Ozone
199136527265235003793187Ozone
199036529153201003977192Ozone
198936526969215104090202Ozone
19883662348523195045122218CO
1987365271603040038100182Ozone
198628921256201004187164Ozone
1985220128671960047108192Ozone
1984342261452970034101190Ozone
19833632415836253038143208Ozone
198235727548259003893190Ozone
1981363284452491031100207Ozone
19803572624629182037122202Ozone

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 Indiana with a similar median AQI in 2025

All monitored counties in Indiana

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