Daily Air Quality Index summaries from EPA monitors in Garfield, Colorado, 1985–2025.
69%
Good days in 2025
47
Median daily AQI, 2025
1
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 Garfield, Colorado on 365 days. 252 of those days (69%) were in the Good range, and the median daily AQI was 47. That median is about the same as the typical monitored county in Colorado (median 46 across 27 counties), and higher than the typical monitored U.S. county (40). The main pollutant was ozone on 343 days. Across the years with fuller monitoring, the share of Good days fell: an average of 92% in 1988–2005 versus 58% in 2023–2025.
Years with fewer than 120 monitored days (1999, 2000, 2001, 2002, 2003, 2004…) 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
Ozone
343
94%
Fine particles (PM2.5)
22
6%
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
252
112
1
0
0
0
47
67
131
Ozone
2024
366
216
145
5
0
0
0
49
74
133
Ozone
2023
365
166
196
3
0
0
0
54
77
126
Ozone
2022
365
221
142
2
0
0
0
49
67
108
Ozone
2021
365
198
156
10
1
0
0
49
87
158
Ozone
2020
366
232
129
5
0
0
0
48
75
150
Ozone
2019
365
248
115
2
0
0
0
48
74
105
Ozone
2018
365
214
135
15
1
0
0
48
87
151
Ozone
2017
365
240
124
1
0
0
0
47
71
108
Ozone
2016
366
263
102
1
0
0
0
47
67
126
Ozone
2015
365
260
95
10
0
0
0
45
67
133
Ozone
2014
365
299
64
2
0
0
0
44
58
108
Ozone
2013
365
243
121
1
0
0
0
46
74
101
Ozone
2012
366
142
171
53
0
0
0
61
105
150
Ozone
2011
365
134
202
29
0
0
0
58
97
133
Ozone
2010
365
167
188
10
0
0
0
51
84
150
Ozone
2009
365
284
81
0
0
0
0
45
61
97
Ozone
2008
365
185
171
9
0
0
0
50
84
128
Ozone
2007
324
178
145
0
1
0
0
49
77
166
Ozone
2006
122
114
8
0
0
0
0
30
46
61
PM10
2005
120
115
5
0
0
0
0
24
40
69
PM10
2004
95
94
1
0
0
0
0
19
33
54
PM10
2003
89
89
0
0
0
0
0
17
27
32
PM10
2002
93
92
1
0
0
0
0
18
28
61
PM10
2001
109
109
0
0
0
0
0
18
30
50
PM10
2000
95
95
0
0
0
0
0
18
34
50
PM10
1999
62
60
1
0
0
1
0
19
39
205
PM10
1998
61
57
4
0
0
0
0
22
38
59
PM10
1997
60
58
2
0
0
0
0
22
37
56
PM10
1996
58
51
7
0
0
0
0
22
52
72
PM10
1995
60
53
7
0
0
0
0
25
53
60
PM10
1994
64
54
10
0
0
0
0
27
53
67
PM10
1993
60
49
11
0
0
0
0
32
60
91
PM10
1992
62
56
6
0
0
0
0
26
49
57
PM10
1991
60
52
8
0
0
0
0
28
53
68
PM10
1990
59
52
7
0
0
0
0
28
53
59
PM10
1989
239
209
30
0
0
0
0
29
54
79
PM10
1988
273
251
22
0
0
0
0
27
45
79
PM10
1987
57
54
3
0
0
0
0
22
38
64
PM10
1986
103
73
30
0
0
0
0
32
65
98
PM10
1985
111
100
9
2
0
0
0
28
46
108
PM10
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 Colorado with a similar median AQI in 2025
