EnviroNearby

Fayette County, Tennessee air quality history

Daily Air Quality Index summaries from EPA monitors in Fayette, Tennessee, 1987–1991.

60%
Good days in 1991
46
Median daily AQI, 1991
20
Days above 100 in 1991
204
Days with an AQI in 1991 (of 365)

In 1991, EPA reported a daily Air Quality Index (AQI) for Fayette, Tennessee on 204 days. 123 of those days (60%) were in the Good range, and the median daily AQI was 46. That median is higher than the typical monitored county in Tennessee (median 42 across 17 counties), and higher than the typical monitored U.S. county (39). The main pollutant was ozone on 204 days.

EPA did not report an AQI for every day of 1991 here (204 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 1991; EPA's files for 1992–2025 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 103 of 164 days1987: Moderate 47 of 164 days1987: Unhealthy for Sensitive Groups 11 of 164 days1987: Unhealthy 3 of 164 days19871988: Good 41 of 128 days1988: Moderate 40 of 128 days1988: Unhealthy for Sensitive Groups 37 of 128 days1988: Unhealthy 9 of 128 days1988: Very Unhealthy 1 of 128 days19881989: Good 136 of 180 days1989: Moderate 40 of 180 days1989: Unhealthy for Sensitive Groups 3 of 180 days1989: Unhealthy 1 of 180 days19891990: Good 120 of 161 days1990: Moderate 34 of 161 days1990: Unhealthy for Sensitive Groups 6 of 161 days1990: Unhealthy 1 of 161 days19901991: Good 123 of 204 days1991: Moderate 61 of 204 days1991: Unhealthy for Sensitive Groups 20 of 204 days1991
  • 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 971988: 90th percentile AQI 1431989: 90th percentile AQI 741990: 90th percentile AQI 841991: 90th percentile AQI 971987: Median AQI 451988: Median AQI 771989: Median AQI 421990: Median AQI 421991: Median AQI 4619871988198919901991
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 1991

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
Ozone204100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
199120412361200004697140Ozone
19901611203461004284154Ozone
19891801364031004274164Ozone
198812841403791077143201Ozone
198716410347113004597172Ozone

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 Tennessee

Source: U.S. EPA AirData, “Annual AQI by County” files for 1987–1991 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem