Daily Air Quality Index summaries from EPA monitors in Warren, Kentucky, 1982–2025.
78%
Good days in 2025
39
Median daily AQI, 2025
0
Days above 100 in 2025
365
Days with an AQI in 2025 (of 365)
In 2025, EPA reported a daily Air Quality Index (AQI) for Warren, Kentucky on 365 days. 284 of those days (78%) were in the Good range, and the median daily AQI was 39. That median is about the same as the typical monitored county in Kentucky (median 39 across 25 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 205 days. Across the years with fuller monitoring, the share of Good days rose: an average of 55% in 2000–2002 versus 74% in 2023–2025.
Years with fewer than 120 monitored days (1994, 1995, 1996, 1997, 1998, 1999…) 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.
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 daily AQI
90th-percentile daily AQI
Main pollutant by day, 2025
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.
Pollutant
Days as main pollutant
Share of monitored days
Fine particles (PM2.5)
205
56%
Ozone
160
44%
Year-by-year data
Annual AQI summary by year
Year
Days with AQI
Good
Moderate
Unhealthy for Sensitive Groups
Unhealthy
Very Unhealthy
Hazardous
Median AQI
90th pct.
Max AQI
Main pollutant
2025
365
284
81
0
0
0
0
39
54
73
PM2.5
2024
364
290
74
0
0
0
0
39
54
87
PM2.5
2023
365
238
124
2
1
0
0
44
62
155
PM2.5
2022
363
248
115
0
0
0
0
43
58
84
PM2.5
2021
363
218
143
2
0
0
0
45
65
117
PM2.5
2020
366
237
129
0
0
0
0
44
58
97
PM2.5
2019
348
237
111
0
0
0
0
44
58
76
PM2.5
2018
352
202
150
0
0
0
0
48
62
95
PM2.5
2017
363
202
161
0
0
0
0
48
61
87
PM2.5
2016
365
192
173
0
0
0
0
49
61
93
PM2.5
2015
336
239
97
0
0
0
0
42
58
84
PM2.5
2014
359
235
124
0
0
0
0
44
61
100
PM2.5
2013
359
231
128
0
0
0
0
44
62
83
PM2.5
2012
359
206
137
16
0
0
0
47
74
150
PM2.5
2011
361
174
187
0
0
0
0
52
67
100
PM2.5
2010
364
177
185
2
0
0
0
51
68
105
PM2.5
2009
357
211
146
0
0
0
0
46
63
97
PM2.5
2008
364
174
189
1
0
0
0
52
71
108
PM2.5
2007
365
141
202
22
0
0
0
55
90
136
PM2.5
2006
356
228
126
2
0
0
0
44
74
136
Ozone
2005
365
206
144
15
0
0
0
47
87
122
Ozone
2004
366
238
127
1
0
0
0
44
71
105
Ozone
2003
362
214
135
13
0
0
0
46
84
129
Ozone
2002
364
207
123
27
7
0
0
47
100
185
Ozone
2001
365
206
140
17
2
0
0
46
90
172
Ozone
2000
366
186
157
18
5
0
0
50
90
182
Ozone
1999
114
24
86
4
0
0
0
61
86
114
PM2.5
1998
60
60
0
0
0
0
0
17
33
42
PM10
1997
61
61
0
0
0
0
0
17
31
48
PM10
1996
61
61
0
0
0
0
0
17
28
45
PM10
1995
61
61
0
0
0
0
0
19
36
48
PM10
1994
61
60
1
0
0
0
0
18
37
54
PM10
1993
59
57
2
0
0
0
0
18
38
60
PM10
1992
61
61
0
0
0
0
0
19
32
50
PM10
1991
41
40
1
0
0
0
0
23
35
57
PM10
1982
1
0
0
0
1
0
0
192
192
192
Ozone
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 2025
