EnviroNearby

Johnson County, Indiana air quality history

Daily Air Quality Index summaries from EPA monitors in Johnson, Indiana, 1987–2017.

90%
Good days in 2017
39
Median daily AQI, 2017
0
Days above 100 in 2017
237
Days with an AQI in 2017 (of 365)

In 2017, EPA reported a daily Air Quality Index (AQI) for Johnson, Indiana on 237 days. 214 of those days (90%) were in the Good range, and the median daily AQI was 39. That median is lower than the typical monitored county in Indiana (median 42 across 37 counties), and about the same as the typical monitored U.S. county (41). The main pollutant was ozone on 237 days. Across the years with fuller monitoring, the share of Good days rose: an average of 44% in 1987–1998 versus 88% in 2015–2017.

EPA did not report an AQI for every day of 2017 here (237 of 365 days). Figures describe monitored days only; seasonal monitoring (for example, ozone measured only in warmer months) can make a county look cleaner or dirtier than a full-year record would.

The most recent year with data for this county is 2017; EPA's files for 2018–2025 contain no row for it, which usually means its monitors stopped reporting.

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%1987: Good 85 of 186 days1987: Moderate 57 of 186 days1987: Unhealthy for Sensitive Groups 37 of 186 days1987: Unhealthy 7 of 186 days19871997: Good 99 of 183 days1997: Moderate 61 of 183 days1997: Unhealthy for Sensitive Groups 21 of 183 days1997: Unhealthy 2 of 183 days1998: Good 46 of 143 days1998: Moderate 65 of 143 days1998: Unhealthy for Sensitive Groups 22 of 143 days1998: Unhealthy 10 of 143 days19981999: Good 78 of 179 days1999: Moderate 59 of 179 days1999: Unhealthy for Sensitive Groups 35 of 179 days1999: Unhealthy 7 of 179 days2000: Good 103 of 183 days2000: Moderate 66 of 183 days2000: Unhealthy for Sensitive Groups 12 of 183 days2000: Unhealthy 2 of 183 days20002001: Good 95 of 179 days2001: Moderate 64 of 179 days2001: Unhealthy for Sensitive Groups 19 of 179 days2001: Unhealthy 1 of 179 days2002: Good 86 of 183 days2002: Moderate 61 of 183 days2002: Unhealthy for Sensitive Groups 27 of 183 days2002: Unhealthy 8 of 183 days2002: Very Unhealthy 1 of 183 days20022003: Good 95 of 183 days2003: Moderate 64 of 183 days2003: Unhealthy for Sensitive Groups 22 of 183 days2003: Unhealthy 2 of 183 days2004: Good 131 of 183 days2004: Moderate 47 of 183 days2004: Unhealthy for Sensitive Groups 5 of 183 days20042005: Good 104 of 183 days2005: Moderate 69 of 183 days2005: Unhealthy for Sensitive Groups 9 of 183 days2005: Unhealthy 1 of 183 days2006: Good 115 of 180 days2006: Moderate 54 of 180 days2006: Unhealthy for Sensitive Groups 11 of 180 days20062007: Good 90 of 182 days2007: Moderate 66 of 182 days2007: Unhealthy for Sensitive Groups 25 of 182 days2007: Unhealthy 1 of 182 days2008: Good 126 of 179 days2008: Moderate 52 of 179 days2008: Unhealthy for Sensitive Groups 1 of 179 days20082009: Good 136 of 179 days2009: Moderate 39 of 179 days2009: Unhealthy for Sensitive Groups 4 of 179 days2010: Good 132 of 183 days2010: Moderate 49 of 183 days2010: Unhealthy for Sensitive Groups 2 of 183 days20102011: Good 129 of 178 days2011: Moderate 49 of 178 days2012: Good 109 of 182 days2012: Moderate 64 of 182 days2012: Unhealthy for Sensitive Groups 9 of 182 days20122013: Good 159 of 180 days2013: Moderate 21 of 180 days2014: Good 170 of 176 days2014: Moderate 6 of 176 days20142015: Good 158 of 179 days2015: Moderate 21 of 179 days2016: Good 158 of 183 days2016: Moderate 25 of 183 days20162017: Good 214 of 237 days2017: Moderate 23 of 237 days2017
  • 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 year0501001501987: 90th percentile AQI 1291997: 90th percentile AQI 1081998: 90th percentile AQI 1401999: 90th percentile AQI 1292000: 90th percentile AQI 902001: 90th percentile AQI 1012002: 90th percentile AQI 1292003: 90th percentile AQI 1052004: 90th percentile AQI 712005: 90th percentile AQI 902006: 90th percentile AQI 902007: 90th percentile AQI 1122008: 90th percentile AQI 772009: 90th percentile AQI 742010: 90th percentile AQI 742011: 90th percentile AQI 742012: 90th percentile AQI 902013: 90th percentile AQI 542014: 90th percentile AQI 472015: 90th percentile AQI 512016: 90th percentile AQI 542017: 90th percentile AQI 501987: Median AQI 611997: Median AQI 501998: Median AQI 711999: Median AQI 612000: Median AQI 482001: Median AQI 492002: Median AQI 542003: Median AQI 502004: Median AQI 452005: Median AQI 482006: Median AQI 472007: Median AQI 512008: Median AQI 462009: Median AQI 442010: Median AQI 442011: Median AQI 442012: Median AQI 472013: Median AQI 422014: Median AQI 372015: Median AQI 392016: Median AQI 382017: Median AQI 39198719982000200220042006200820102012201420162017
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2017

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
Ozone237100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2017237214230000395080Ozone
20161831582500003854100Ozone
2015179158210000395190Ozone
201417617060000374771Ozone
2013180159210000425493Ozone
20121821096490004790140Ozone
20111781294900004474100Ozone
20101831324920004474105Ozone
20091791363940004474126Ozone
20081791265210004677119Ozone
200718290662510051112161Ozone
200618011554110004790136Ozone
20051831046991004890164Ozone
20041831314750004571129Ozone
200318395642220050105164Ozone
200218386612781054129206Ozone
200117995641910049101151Ozone
200018310366122004890164Ozone
199917978593570061129185Ozone
1998143466522100071140169Ozone
199718399612120050108174Ozone
198718685573770061129185Ozone

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.

All monitored counties in Indiana

Source: U.S. EPA AirData, “Annual AQI by County” files for 1987–2017 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem