EnviroNearby

Boone County, Indiana air quality history

Daily Air Quality Index summaries from EPA monitors in Boone, Indiana, 2000–2025.

90%
Good days in 2025
35
Median daily AQI, 2025
3
Days above 100 in 2025
350
Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Boone, Indiana on 350 days. 314 of those days (90%) 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 350 days. Across the years with fuller monitoring, the share of Good days rose: an average of 54% in 2000–2002 versus 87% 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%2000: Good 113 of 183 days2000: Moderate 57 of 183 days2000: Unhealthy for Sensitive Groups 11 of 183 days2000: Unhealthy 2 of 183 days20002001: Good 100 of 183 days2001: Moderate 53 of 183 days2001: Unhealthy for Sensitive Groups 28 of 183 days2001: Unhealthy 2 of 183 days2002: Good 82 of 183 days2002: Moderate 63 of 183 days2002: Unhealthy for Sensitive Groups 25 of 183 days2002: Unhealthy 11 of 183 days2002: Very Unhealthy 2 of 183 days20022003: Good 92 of 183 days2003: Moderate 64 of 183 days2003: Unhealthy for Sensitive Groups 22 of 183 days2003: Unhealthy 5 of 183 days2004: Good 126 of 183 days2004: Moderate 52 of 183 days2004: Unhealthy for Sensitive Groups 4 of 183 days2004: Unhealthy 1 of 183 days20042005: Good 97 of 183 days2005: Moderate 59 of 183 days2005: Unhealthy for Sensitive Groups 26 of 183 days2005: Unhealthy 1 of 183 days2006: Good 119 of 183 days2006: Moderate 53 of 183 days2006: Unhealthy for Sensitive Groups 10 of 183 days2006: Unhealthy 1 of 183 days20062007: Good 106 of 183 days2007: Moderate 52 of 183 days2007: Unhealthy for Sensitive Groups 25 of 183 days2008: Good 128 of 183 days2008: Moderate 51 of 183 days2008: Unhealthy for Sensitive Groups 4 of 183 days20082009: Good 134 of 181 days2009: Moderate 46 of 181 days2009: Unhealthy for Sensitive Groups 1 of 181 days2010: Good 125 of 183 days2010: Moderate 51 of 183 days2010: Unhealthy for Sensitive Groups 7 of 183 days20102011: Good 149 of 204 days2011: Moderate 51 of 204 days2011: Unhealthy for Sensitive Groups 3 of 204 days2011: Unhealthy 1 of 204 days2012: Good 99 of 171 days2012: Moderate 56 of 171 days2012: Unhealthy for Sensitive Groups 15 of 171 days2012: Unhealthy 1 of 171 days20122013: Good 143 of 183 days2013: Moderate 38 of 183 days2013: Unhealthy for Sensitive Groups 2 of 183 days2014: Good 143 of 183 days2014: Moderate 38 of 183 days2014: Unhealthy for Sensitive Groups 2 of 183 days20142015: Good 144 of 176 days2015: Moderate 32 of 176 days2016: Good 143 of 181 days2016: Moderate 35 of 181 days2016: Unhealthy for Sensitive Groups 3 of 181 days20162017: Good 219 of 245 days2017: Moderate 25 of 245 days2017: Unhealthy for Sensitive Groups 1 of 245 days2018: Good 324 of 365 days2018: Moderate 36 of 365 days2018: Unhealthy for Sensitive Groups 5 of 365 days20182019: Good 320 of 351 days2019: Moderate 31 of 351 days2020: Good 330 of 352 days2020: Moderate 20 of 352 days2020: Unhealthy for Sensitive Groups 2 of 352 days20202021: Good 337 of 365 days2021: Moderate 27 of 365 days2021: Unhealthy for Sensitive Groups 1 of 365 days2022: Good 331 of 362 days2022: Moderate 30 of 362 days2022: Unhealthy for Sensitive Groups 1 of 362 days20222023: Good 307 of 362 days2023: Moderate 46 of 362 days2023: Unhealthy for Sensitive Groups 8 of 362 days2023: Unhealthy 1 of 362 days2024: Good 313 of 359 days2024: Moderate 46 of 359 days20242025: Good 314 of 350 days2025: Moderate 33 of 350 days2025: Unhealthy for Sensitive Groups 3 of 350 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 year0501001502000: 90th percentile AQI 902001: 90th percentile AQI 1122002: 90th percentile AQI 1292003: 90th percentile AQI 1122004: 90th percentile AQI 772005: 90th percentile AQI 1152006: 90th percentile AQI 872007: 90th percentile AQI 1012008: 90th percentile AQI 802009: 90th percentile AQI 742010: 90th percentile AQI 902011: 90th percentile AQI 772012: 90th percentile AQI 972013: 90th percentile AQI 642014: 90th percentile AQI 642015: 90th percentile AQI 612016: 90th percentile AQI 712017: 90th percentile AQI 512018: 90th percentile AQI 542019: 90th percentile AQI 502020: 90th percentile AQI 482021: 90th percentile AQI 482022: 90th percentile AQI 502023: 90th percentile AQI 612024: 90th percentile AQI 512025: 90th percentile AQI 512000: Median AQI 472001: Median AQI 482002: Median AQI 542003: Median AQI 502004: Median AQI 452005: Median AQI 502006: Median AQI 452007: Median AQI 482008: Median AQI 452009: Median AQI 442010: Median AQI 452011: Median AQI 432012: Median AQI 492013: Median AQI 432014: Median AQI 422015: Median AQI 422016: Median AQI 402017: Median AQI 392018: Median AQI 342019: Median AQI 352020: Median AQI 322021: Median AQI 332022: Median AQI 362023: Median AQI 372024: Median AQI 362025: Median AQI 3520002002200420062008201020122014201620182020202220242025
  • 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
Ozone350100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
20253503143330003551112Ozone
2024359313460000365193Ozone
20233623074681003761185Ozone
20223623313010003650115Ozone
20213653372710003348101Ozone
20203523302020003248101Ozone
2019351320310000355090Ozone
20183653243650003454112Ozone
20172452192510003951101Ozone
20161811433530004071126Ozone
2015176144320000426197Ozone
20141831433820004264108Ozone
20131831433820004364112Ozone
20121719956151004997164Ozone
20112041495131004377159Ozone
20101831255170004590122Ozone
20091811344610004474108Ozone
20081831285140004580115Ozone
2007183106522500048101150Ozone
200618311953101004587156Ozone
200518397592610050115156Ozone
20041831265241004577159Ozone
200318392642250050112190Ozone
2002183826325112054129210Ozone
2001183100532820048112177Ozone
200018311357112004790166Ozone

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 2000–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem