EnviroNearby

Muhlenberg County, Kentucky air quality history

Daily Air Quality Index summaries from EPA monitors in Muhlenberg, Kentucky, 1980–2002.

90%
Good days in 2002
35
Median daily AQI, 2002
0
Days above 100 in 2002
120
Days with an AQI in 2002 (of 365)

In 2002, EPA reported a daily Air Quality Index (AQI) for Muhlenberg, Kentucky on 120 days. 108 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 Kentucky (median 44 across 32 counties), and lower than the typical monitored U.S. county (44). The main pollutant was ozone on 106 days. Across the years with fuller monitoring, the share of Good days fell: an average of 76% in 1980–1982 versus 64% in 1987–2002.

EPA did not report an AQI for every day of 2002 here (120 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 2002; EPA's files for 2003–2025 contain no row for it, which usually means its monitors stopped reporting.

Years with fewer than 120 monitored days (1986, 1988) 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%1980: Good 256 of 352 days1980: Moderate 73 of 352 days1980: Unhealthy for Sensitive Groups 16 of 352 days1980: Unhealthy 6 of 352 days1980: Very Unhealthy 1 of 352 days19801981: Good 253 of 338 days1981: Moderate 62 of 338 days1981: Unhealthy for Sensitive Groups 22 of 338 days1981: Unhealthy 1 of 338 days19811982: Good 253 of 319 days1982: Moderate 48 of 319 days1982: Unhealthy for Sensitive Groups 17 of 319 days1982: Unhealthy 1 of 319 days19821983: Good 239 of 346 days1983: Moderate 55 of 346 days1983: Unhealthy for Sensitive Groups 40 of 346 days1983: Unhealthy 11 of 346 days1983: Very Unhealthy 1 of 346 days19831984: Good 104 of 187 days1984: Moderate 57 of 187 days1984: Unhealthy for Sensitive Groups 25 of 187 days1984: Unhealthy 1 of 187 days19841985: Good 147 of 189 days1985: Moderate 40 of 189 days1985: Unhealthy for Sensitive Groups 2 of 189 days19851986: Good 26 of 30 days1986: Moderate 4 of 30 days19861987: Good 69 of 150 days1987: Moderate 60 of 150 days1987: Unhealthy for Sensitive Groups 21 of 150 days19871988: Good 21 of 38 days1988: Moderate 15 of 38 days1988: Unhealthy for Sensitive Groups 2 of 38 days19882001: Good 138 of 245 days2001: Moderate 77 of 245 days2001: Unhealthy for Sensitive Groups 28 of 245 days2001: Unhealthy 2 of 245 days20012002: Good 108 of 120 days2002: Moderate 12 of 120 days2002
  • 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 year0501001501980: 90th percentile AQI 901981: 90th percentile AQI 871982: 90th percentile AQI 801983: 90th percentile AQI 1081984: 90th percentile AQI 1151985: 90th percentile AQI 711986: 90th percentile AQI 511987: 90th percentile AQI 1081988: 90th percentile AQI 902001: 90th percentile AQI 1052002: 90th percentile AQI 511980: Median AQI 381981: Median AQI 361982: Median AQI 361983: Median AQI 391984: Median AQI 491985: Median AQI 421986: Median AQI 381987: Median AQI 541988: Median AQI 492001: Median AQI 472002: Median AQI 3519801981198219831984198519861987198820012002
  • Median daily AQI
  • 90th-percentile daily AQI

Main pollutant by day, 2002

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
Ozone10688%
Nitrogen dioxide (NO₂)1412%

Year-by-year data

Annual AQI summary by year
YearDays with AQIGoodModerateUnhealthy for Sensitive GroupsUnhealthyVery UnhealthyHazardousMedian AQI90th pct.Max AQIMain pollutant
2002120108120000355197Ozone
2001245138772820047105185Ozone
198838211520004990108Ozone
198715069602100054108147Ozone
1986302640000385190Ozone
19851891474020004271115Ozone
1984187104572510049115156Ozone
19833462395540111039108204Ozone
198231925348171003680154Ozone
198133825362221003687154Ozone
198035225673166103890201Ozone

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 Kentucky

Source: U.S. EPA AirData, “Annual AQI by County” files for 1980–2002 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem