EnviroNearby

Posey County, Indiana air quality history

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

91%
Good days in 2025
35
Median daily AQI, 2025
1
Days above 100 in 2025
338
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Posey, Indiana on 338 days. 306 of those days (91%) were in the Good range, and the median daily AQI was 35. That median is lower than the typical monitored county in Indiana (median 41 across 33 counties), and lower than the typical monitored U.S. county (40). The main pollutant was ozone on 338 days. Across the years with fuller monitoring, the share of Good days held roughly steady: an average of 92% in 1981–1983 versus 90% in 2023–2025.

Years with fewer than 120 monitored days (1980, 1989, 1996) are shown in the table but left out of comparisons and trend statements.

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 48 of 48 days19801981: Good 184 of 240 days1981: Moderate 56 of 240 days1982: Good 235 of 236 days1982: Very Unhealthy 1 of 236 days1983: Good 282 of 284 days1983: Moderate 1 of 284 days1983: Unhealthy for Sensitive Groups 1 of 284 days1984: Good 260 of 265 days1984: Moderate 2 of 265 days1984: Unhealthy for Sensitive Groups 3 of 265 days1985: Good 179 of 203 days1985: Moderate 22 of 203 days1985: Unhealthy for Sensitive Groups 2 of 203 days19851986: Good 358 of 362 days1986: Moderate 4 of 362 days1987: Good 350 of 351 days1987: Moderate 1 of 351 days1988: Good 121 of 152 days1988: Moderate 25 of 152 days1988: Unhealthy for Sensitive Groups 6 of 152 days1989: Good 80 of 92 days1989: Moderate 7 of 92 days1989: Unhealthy for Sensitive Groups 5 of 92 days1990: Good 281 of 360 days1990: Moderate 48 of 360 days1990: Unhealthy for Sensitive Groups 25 of 360 days1990: Unhealthy 6 of 360 days19901991: Good 145 of 181 days1991: Moderate 10 of 181 days1991: Unhealthy for Sensitive Groups 7 of 181 days1991: Unhealthy 13 of 181 days1991: Very Unhealthy 6 of 181 days1996: Good 77 of 80 days1996: Moderate 3 of 80 days1997: Good 90 of 181 days1997: Moderate 69 of 181 days1997: Unhealthy for Sensitive Groups 18 of 181 days1997: Unhealthy 4 of 181 days1998: Good 53 of 172 days1998: Moderate 77 of 172 days1998: Unhealthy for Sensitive Groups 34 of 172 days1998: Unhealthy 7 of 172 days1998: Very Unhealthy 1 of 172 days1999: Good 82 of 183 days1999: Moderate 63 of 183 days1999: Unhealthy for Sensitive Groups 24 of 183 days1999: Unhealthy 14 of 183 days19992000: Good 84 of 183 days2000: Moderate 73 of 183 days2000: Unhealthy for Sensitive Groups 23 of 183 days2000: Unhealthy 3 of 183 days2001: Good 100 of 179 days2001: Moderate 60 of 179 days2001: Unhealthy for Sensitive Groups 19 of 179 days2002: Good 86 of 175 days2002: Moderate 56 of 175 days2002: Unhealthy for Sensitive Groups 20 of 175 days2002: Unhealthy 12 of 175 days2002: Very Unhealthy 1 of 175 days2003: Good 109 of 183 days2003: Moderate 63 of 183 days2003: Unhealthy for Sensitive Groups 10 of 183 days2003: Unhealthy 1 of 183 days2004: Good 129 of 180 days2004: Moderate 47 of 180 days2004: Unhealthy for Sensitive Groups 4 of 180 days20042005: Good 98 of 176 days2005: Moderate 61 of 176 days2005: Unhealthy for Sensitive Groups 17 of 176 days2006: Good 166 of 176 days2006: Moderate 9 of 176 days2006: Unhealthy for Sensitive Groups 1 of 176 days2007: Good 87 of 181 days2007: Moderate 64 of 181 days2007: Unhealthy for Sensitive Groups 29 of 181 days2007: Unhealthy 1 of 181 days2008: Good 134 of 173 days2008: Moderate 37 of 173 days2008: Unhealthy for Sensitive Groups 2 of 173 days2009: Good 153 of 183 days2009: Moderate 29 of 183 days2009: Unhealthy for Sensitive Groups 1 of 183 days20092010: Good 133 of 180 days2010: Moderate 44 of 180 days2010: Unhealthy for Sensitive Groups 3 of 180 days2011: Good 125 of 172 days2011: Moderate 40 of 172 days2011: Unhealthy for Sensitive Groups 7 of 172 days2012: Good 113 of 153 days2012: Moderate 38 of 153 days2012: Unhealthy for Sensitive Groups 2 of 153 days2013: Good 159 of 183 days2013: Moderate 24 of 183 days2014: Good 147 of 181 days2014: Moderate 34 of 181 days20142015: Good 156 of 183 days2015: Moderate 25 of 183 days2015: Unhealthy for Sensitive Groups 2 of 183 days2016: Good 148 of 181 days2016: Moderate 32 of 181 days2016: Unhealthy for Sensitive Groups 1 of 181 days2017: Good 189 of 229 days2017: Moderate 38 of 229 days2017: Unhealthy for Sensitive Groups 2 of 229 days2018: Good 326 of 360 days2018: Moderate 34 of 360 days2019: Good 341 of 364 days2019: Moderate 23 of 364 days20192020: Good 336 of 355 days2020: Moderate 18 of 355 days2020: Unhealthy for Sensitive Groups 1 of 355 days2021: Good 344 of 360 days2021: Moderate 16 of 360 days2022: Good 349 of 364 days2022: Moderate 15 of 364 days2023: Good 304 of 354 days2023: Moderate 43 of 354 days2023: Unhealthy for Sensitive Groups 7 of 354 days2024: Good 340 of 365 days2024: Moderate 24 of 365 days2024: Unhealthy for Sensitive Groups 1 of 365 days20242025: Good 306 of 338 days2025: Moderate 31 of 338 days2025: Unhealthy for Sensitive Groups 1 of 338 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 341981: 90th percentile AQI 831982: 90th percentile AQI 211983: 90th percentile AQI 281984: 90th percentile AQI 361985: 90th percentile AQI 541986: 90th percentile AQI 351987: 90th percentile AQI 341988: 90th percentile AQI 851989: 90th percentile AQI 671990: 90th percentile AQI 931991: 90th percentile AQI 1511996: 90th percentile AQI 481997: 90th percentile AQI 1081998: 90th percentile AQI 1291999: 90th percentile AQI 1362000: 90th percentile AQI 1192001: 90th percentile AQI 1052002: 90th percentile AQI 1332003: 90th percentile AQI 932004: 90th percentile AQI 772005: 90th percentile AQI 1002006: 90th percentile AQI 472007: 90th percentile AQI 1082008: 90th percentile AQI 642009: 90th percentile AQI 612010: 90th percentile AQI 802011: 90th percentile AQI 772012: 90th percentile AQI 712013: 90th percentile AQI 542014: 90th percentile AQI 672015: 90th percentile AQI 542016: 90th percentile AQI 642017: 90th percentile AQI 582018: 90th percentile AQI 502019: 90th percentile AQI 492020: 90th percentile AQI 452021: 90th percentile AQI 452022: 90th percentile AQI 452023: 90th percentile AQI 612024: 90th percentile AQI 492025: 90th percentile AQI 501980: Median AQI 251981: Median AQI 281982: Median AQI 111983: Median AQI 161984: Median AQI 211985: Median AQI 151986: Median AQI 221987: Median AQI 181988: Median AQI 191989: Median AQI 231990: Median AQI 351991: Median AQI 311996: Median AQI 371997: Median AQI 511998: Median AQI 741999: Median AQI 582000: Median AQI 542001: Median AQI 492002: Median AQI 512003: Median AQI 472004: Median AQI 452005: Median AQI 472006: Median AQI 342007: Median AQI 512008: Median AQI 442009: Median AQI 412010: Median AQI 432011: Median AQI 442012: Median AQI 432013: Median AQI 412014: Median AQI 432015: Median AQI 402016: Median AQI 392017: Median AQI 422018: Median AQI 342019: Median AQI 352020: Median AQI 312021: Median AQI 322022: Median AQI 332023: Median AQI 382024: Median AQI 372025: Median AQI 351980198519901999200420092014201920242025
  • 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
Ozone338100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253383063110003550105Ozone
20243653402410003749122Ozone
20233543044370003861126Ozone
2022364349150000334597Ozone
2021360344160000324577Ozone
20203553361810003145112Ozone
2019364341230000354980Ozone
20183603263400003450100Ozone
20172291893820004258126Ozone
20161811483210003964112Ozone
20151831562520004054115Ozone
20141811473400004367100Ozone
20131831592400004154100Ozone
20121531133820004371108Ozone
20111721254070004477129Ozone
20101801334430004380105Ozone
20091831532910004161119Ozone
20081731343720004464133Ozone
200718187642910051108151Ozone
2006176166910003447129Ozone
200517698611700047100150Ozone
20041801294740004577122Ozone
200318310963101004793166Ozone
2002175865620121051133201Ozone
2001179100601900049105133Ozone
200018384732330054119169Ozone
1999183826324140058136200Ozone
199817253773471074129206Ozone
199718190691840051108177Ozone
1996807730000374871Ozone
1991181145107136031151204Ozone
199036028148256003593185Ozone
19899280750002367143NO2
19881521212560001985141NO2
198735135010000183455NO2
198636235840000223563NO2
19852031792220001554102NO2
1984265260230002136109NO2
1983284282110001628110NO2
1982236235000101121259NO2
1981240184560000288397NO2
1980484800000253444NO2

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