EnviroNearby

Vermillion County, Indiana air quality history

Daily Air Quality Index summaries from EPA monitors in Vermillion, Indiana, 1988–1998.

93%
Good days in 1992
19
Median daily AQI, 1992
0
Days above 100 in 1992
184
Days with an AQI in 1992 (of 366)

In 1992, EPA reported a daily Air Quality Index (AQI) for Vermillion, Indiana on 184 days. 171 of those days (93%) were in the Good range, and the median daily AQI was 19. That median is lower than the typical monitored county in Indiana (median 36 across 19 counties), and lower than the typical monitored U.S. county (37). The main pollutant was coarse particles (PM10) on 184 days.

EPA did not report an AQI for every day of 1992 here (184 of 366 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 1998; EPA's files for 1999–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (1993, 1994, 1995, 1996, 1997, 1998) 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%1988: Good 101 of 142 days1988: Moderate 39 of 142 days1988: Unhealthy for Sensitive Groups 2 of 142 days19881989: Good 143 of 176 days1989: Moderate 33 of 176 days19891990: Good 139 of 165 days1990: Moderate 26 of 165 days19901991: Good 154 of 176 days1991: Moderate 22 of 176 days19911992: Good 171 of 184 days1992: Moderate 13 of 184 days19921993: Good 62 of 64 days1993: Moderate 2 of 64 days19931994: Good 59 of 61 days1994: Moderate 2 of 61 days19941995: Good 56 of 60 days1995: Moderate 4 of 60 days19951996: Good 55 of 56 days1996: Moderate 1 of 56 days19961997: Good 61 of 61 days19971998: Good 17 of 17 days1998
  • 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 year0501001988: 90th percentile AQI 681989: 90th percentile AQI 561990: 90th percentile AQI 541991: 90th percentile AQI 521992: 90th percentile AQI 451993: 90th percentile AQI 351994: 90th percentile AQI 381995: 90th percentile AQI 451996: 90th percentile AQI 351997: 90th percentile AQI 361998: 90th percentile AQI 291988: Median AQI 341989: Median AQI 301990: Median AQI 291991: Median AQI 271992: Median AQI 191993: Median AQI 171994: Median AQI 191995: Median AQI 181996: Median AQI 161997: Median AQI 171998: Median AQI 1419881989199019911992199319941995199619971998
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 1992

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
Coarse particles (PM10)184100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
1998171700000142930PM10
1997616100000173646PM10
1996565510000163552PM10
1995605640000184555PM10
1994615920000193854PM10
1993646220000173557PM10
1992184171130000194565PM10
1991176154220000275289PM10
1990165139260000295478PM10
1989176143330000305691PM10
19881421013920003468124PM10

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 1988–1998 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem