Bad Air Days in Warren County, Kentucky: under 1 a Year

under 1 bad air day a year

Rare: among the cleanest-air counties EPA monitors. Ranked 816 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly particles: smoke and dust (80% particle days).

Which months to watch

Most bad days here fall in July and June. Averaged over 2016 to 2025.

What actually helps here

Bad air days are rare here. A standard furnace filter is enough; no purifier needed for outdoor air.
On the odd bad day, check AirNow and keep windows shut.

Better or worse than it was

In 2000 to 2009 this county averaged 13 bad days a year; in 2016 to 2025, under 1. The air has improved. The worst recent year was 2023, with 3 bad days on 365 monitored days.

Date	AQI	Main pollutant
2023-06-28	155	PM2.5
2021-07-21	117	PM2.5
2023-07-16	111	PM2.5
2021-07-31	107	PM2.5
2023-06-10	101	Ozone

Most days, not the worst ones

Across 3,614 monitored days from 2016 to 2025, the air in Warren County rated Good on 65% of them, less often than the 72% typical of monitored counties, and Moderate on 35%. The median day sat at AQI 44; one day in ten went above 59.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)73%2,654 days
ozone27%960 days

Warren County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	284	81	0	0	39	73
2024	364	290	74	0	0	39	87
2023	365	238	124	3	1	44	155
2022	363	248	115	0	0	43	84
2021	363	218	143	2	0	45	117
2020	366	237	129	0	0	44	97
2019	348	237	111	0	0	44	76
2018	352	202	150	0	0	48	95
2017	363	202	161	0	0	48	87
2016	365	192	173	0	0	49	93
2015	336	239	97	0	0	42	84
2014	359	235	124	0	0	44	100
2013	359	231	128	0	0	44	83
2012	359	206	137	16	0	47	150
2011	361	174	187	0	0	52	100
2010	364	177	185	2	0	51	105

*2025 may be a partial year in EPA's file.

Kentucky compared

How this is counted

A bad air day is a day the county's daily AQI from EPA AirData went above 100, the level where EPA tells children, older adults and people with asthma or heart disease to cut back outdoors. Monitors do not run every day, so yearly counts are scaled to 365 days. This is the record, not today's air: for that, check AirNow. More on the method in how the county numbers are made, on the AQI 100 line in what counts as a bad air day.