EnviroNearby

Clay County, Kentucky air quality history

Daily Air Quality Index summaries from EPA monitors in Clay, Kentucky, 1981–1983.

62%
Good days in 1983
45
Median daily AQI, 1983
18
Days above 100 in 1983
184
Days with an AQI in 1983 (of 365)

In 1983, EPA reported a daily Air Quality Index (AQI) for Clay, Kentucky on 184 days. 115 of those days (62%) were in the Good range, and the median daily AQI was 45. That median is about the same as the typical monitored county in Kentucky (median 45 across 31 counties), and higher than the typical monitored U.S. county (40). The main pollutant was ozone on 184 days.

EPA did not report an AQI for every day of 1983 here (184 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 1983; EPA's files for 1984–2025 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%1981: Good 111 of 144 days1981: Moderate 31 of 144 days1981: Unhealthy for Sensitive Groups 2 of 144 days19811982: Good 157 of 171 days1982: Moderate 14 of 171 days19821983: Good 115 of 184 days1983: Moderate 51 of 184 days1983: Unhealthy for Sensitive Groups 16 of 184 days1983: Unhealthy 2 of 184 days1983
  • 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 year0501001981: 90th percentile AQI 741982: 90th percentile AQI 491983: 90th percentile AQI 971981: Median AQI 411982: Median AQI 391983: Median AQI 45198119821983
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 1983

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
Ozone184100%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
198318411551162004597164Ozone
1982171157140000394990Ozone
19811441113120004174105Ozone

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 Kentucky with a similar median AQI in 1983

All monitored counties in Kentucky

Source: U.S. EPA AirData, “Annual AQI by County” files for 1981–1983 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem