Daily Air Quality Index summaries from EPA monitors in Gilmer, West Virginia, 1990–2022.
98%
Good days in 2021
31
Median daily AQI, 2021
0
Days above 100 in 2021
358
Days with an AQI in 2021 (of 365)
In 2021, EPA reported a daily Air Quality Index (AQI) for Gilmer, West Virginia on 358 days. 350 of those days (98%) were in the Good range, and the median daily AQI was 31. That median is lower than the typical monitored county in West Virginia (median 38 across 12 counties), and lower than the typical monitored U.S. county (41). The main pollutant was ozone on 358 days. Across the years with fuller monitoring, the share of Good days rose: an average of 80% in 1990–1992 versus 99% in 2019–2021.
The most recent year with data for this county is 2022; EPA's files for 2023–2025 contain no row for it, which usually means its monitors stopped reporting.
Years with fewer than 120 monitored days (2022) 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, 2021
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
Ozone
358
100%
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
2022
110
108
2
0
0
0
0
37
47
71
Ozone
2021
358
350
8
0
0
0
0
31
42
74
Ozone
2020
363
363
0
0
0
0
0
29
41
49
Ozone
2019
336
333
3
0
0
0
0
32
44
58
Ozone
2018
360
346
14
0
0
0
0
29
44
90
Ozone
2017
354
351
3
0
0
0
0
31
43
71
Ozone
2016
346
334
11
1
0
0
0
32
44
105
Ozone
2015
346
338
8
0
0
0
0
31
44
67
Ozone
2014
358
348
10
0
0
0
0
31
44
93
Ozone
2013
348
336
12
0
0
0
0
31
44
80
Ozone
2012
356
339
16
1
0
0
0
34
48
129
Ozone
2011
321
306
15
0
0
0
0
33
47
84
Ozone
2010
345
329
16
0
0
0
0
32
47
84
Ozone
2009
358
349
9
0
0
0
0
31
45
87
Ozone
2008
339
320
16
3
0
0
0
34
46
115
Ozone
2007
337
285
49
3
0
0
0
38
64
126
Ozone
2006
355
328
27
0
0
0
0
31
49
97
Ozone
2005
359
327
29
3
0
0
0
31
50
122
Ozone
2004
343
318
25
0
0
0
0
31
46
100
Ozone
2003
363
327
30
6
0
0
0
31
50
126
Ozone
2002
358
301
48
9
0
0
0
33
64
150
Ozone
2001
349
291
47
11
0
0
0
35
64
150
Ozone
2000
347
289
50
7
1
0
0
34
74
151
Ozone
1999
337
233
79
20
5
0
0
42
97
179
Ozone
1998
336
244
62
24
6
0
0
37
93
169
Ozone
1997
362
295
61
5
1
0
0
36
67
169
Ozone
1996
211
160
38
12
1
0
0
35
80
172
Ozone
1995
269
189
67
13
0
0
0
41
87
143
Ozone
1994
353
274
62
15
2
0
0
36
80
169
Ozone
1993
359
281
56
19
3
0
0
35
84
179
Ozone
1992
357
309
45
3
0
0
0
33
61
126
Ozone
1991
358
256
73
25
4
0
0
39
93
187
Ozone
1990
362
293
50
16
3
0
0
36
74
187
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.
