EnviroNearby

Indiana County, Pennsylvania air quality history

Daily Air Quality Index summaries from EPA monitors in Indiana, Pennsylvania, 2004–2025.

75%
Good days in 2025
39
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 Indiana, Pennsylvania on 365 days. 273 of those days (75%) were in the Good range, and the median daily AQI was 39. That median is about the same as the typical monitored county in Pennsylvania (median 40 across 38 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was ozone on 195 days. Across the years with fuller monitoring, the share of Good days fell: an average of 79% in 2005–2007 versus 76% in 2023–2025.

Years with fewer than 120 monitored days (2004) 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%2004: Good 60 of 60 days20042005: Good 273 of 364 days2005: Moderate 61 of 364 days2005: Unhealthy for Sensitive Groups 26 of 364 days2005: Unhealthy 4 of 364 days2006: Good 305 of 365 days2006: Moderate 52 of 365 days2006: Unhealthy for Sensitive Groups 7 of 365 days2006: Unhealthy 1 of 365 days20062007: Good 281 of 359 days2007: Moderate 59 of 359 days2007: Unhealthy for Sensitive Groups 19 of 359 days2008: Good 303 of 363 days2008: Moderate 52 of 363 days2008: Unhealthy for Sensitive Groups 8 of 363 days20082009: Good 182 of 211 days2009: Moderate 27 of 211 days2009: Unhealthy for Sensitive Groups 2 of 211 days2010: Good 133 of 214 days2010: Moderate 67 of 214 days2010: Unhealthy for Sensitive Groups 13 of 214 days2010: Unhealthy 1 of 214 days20102011: Good 255 of 306 days2011: Moderate 44 of 306 days2011: Unhealthy for Sensitive Groups 7 of 306 days2012: Good 276 of 355 days2012: Moderate 63 of 355 days2012: Unhealthy for Sensitive Groups 14 of 355 days2012: Unhealthy 2 of 355 days20122013: Good 305 of 352 days2013: Moderate 42 of 352 days2013: Unhealthy for Sensitive Groups 4 of 352 days2013: Unhealthy 1 of 352 days2014: Good 335 of 365 days2014: Moderate 28 of 365 days2014: Unhealthy for Sensitive Groups 2 of 365 days20142015: Good 300 of 363 days2015: Moderate 59 of 363 days2015: Unhealthy for Sensitive Groups 4 of 363 days2016: Good 309 of 354 days2016: Moderate 41 of 354 days2016: Unhealthy for Sensitive Groups 4 of 354 days20162017: Good 315 of 348 days2017: Moderate 33 of 348 days2018: Good 322 of 355 days2018: Moderate 32 of 355 days2018: Unhealthy for Sensitive Groups 1 of 355 days20182019: Good 324 of 350 days2019: Moderate 26 of 350 days2020: Good 320 of 351 days2020: Moderate 30 of 351 days2020: Unhealthy for Sensitive Groups 1 of 351 days20202021: Good 218 of 348 days2021: Moderate 128 of 348 days2021: Unhealthy for Sensitive Groups 2 of 348 days2022: Good 264 of 365 days2022: Moderate 100 of 365 days2022: Unhealthy for Sensitive Groups 1 of 365 days20222023: Good 264 of 363 days2023: Moderate 92 of 363 days2023: Unhealthy for Sensitive Groups 4 of 363 days2023: Unhealthy 2 of 363 days2023: Very Unhealthy 1 of 363 days2024: Good 291 of 357 days2024: Moderate 66 of 357 days20242025: Good 273 of 365 days2025: Moderate 90 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 year0501002004: 90th percentile AQI 242005: 90th percentile AQI 932006: 90th percentile AQI 672007: 90th percentile AQI 802008: 90th percentile AQI 712009: 90th percentile AQI 612010: 90th percentile AQI 872011: 90th percentile AQI 642012: 90th percentile AQI 772013: 90th percentile AQI 582014: 90th percentile AQI 502015: 90th percentile AQI 612016: 90th percentile AQI 542017: 90th percentile AQI 502018: 90th percentile AQI 502019: 90th percentile AQI 492020: 90th percentile AQI 492021: 90th percentile AQI 632022: 90th percentile AQI 562023: 90th percentile AQI 612024: 90th percentile AQI 562025: 90th percentile AQI 592004: Median AQI 172005: Median AQI 332006: Median AQI 312007: Median AQI 342008: Median AQI 312009: Median AQI 372010: Median AQI 452011: Median AQI 392012: Median AQI 382013: Median AQI 362014: Median AQI 382015: Median AQI 372016: Median AQI 382017: Median AQI 382018: Median AQI 352019: Median AQI 382020: Median AQI 372021: Median AQI 442022: Median AQI 422023: Median AQI 412024: Median AQI 372025: Median AQI 39200420062008201020122014201620182020202220242025
  • 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
Ozone19553%
Fine particles (PM2.5)17047%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253652739020003959122Ozone
2024357291660000375674Ozone
20233632649242104161220PM2.5
202236526410010004256105PM2.5
202134821812820004463122PM2.5
20203513203010003749112Ozone
2019350324260000384993Ozone
20183553223210003550105Ozone
20173483153300003850100Ozone
20163543094140003854136Ozone
20153633005940003761119Ozone
20143653352820003850115Ozone
20133523054241003658169Ozone
201235527663142003877156Ozone
20113062554470003964140Ozone
201021413367131004587159Ozone
20092111822720003761126Ozone
20083633035280003171143Ozone
200735928159190003480140Ozone
20063653055271003167154Ozone
200536427361264003393172Ozone
2004606000000172432NO2

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 Pennsylvania with a similar median AQI in 2025

All monitored counties in Pennsylvania

Source: U.S. EPA AirData, “Annual AQI by County” files for 2004–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem