Daily Air Quality Index summaries from EPA monitors in Stafford, Virginia, 1992–2025.
96%
Good days in 2025
35
Median daily AQI, 2025
0
Days above 100 in 2025
360
Days with an AQI in 2025 (of 365)
In 2025, EPA reported a daily Air Quality Index (AQI) for Stafford, Virginia on 360 days. 347 of those days (96%) were in the Good range, and the median daily AQI was 35. That median is about the same as the typical monitored county in Virginia (median 37 across 25 counties), and lower than the typical monitored U.S. county (40). The main pollutant was ozone on 358 days. Across the years with fuller monitoring, the share of Good days rose: an average of 55% in 1993–1995 versus 95% in 2023–2025.
Years with fewer than 120 monitored days (1992) 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
358
99%
Coarse particles (PM10)
2
1%
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
360
347
13
0
0
0
0
35
46
77
Ozone
2024
362
353
9
0
0
0
0
35
47
90
Ozone
2023
365
332
31
1
1
0
0
37
50
169
Ozone
2022
362
351
11
0
0
0
0
35
44
74
Ozone
2021
358
337
20
1
0
0
0
35
47
115
Ozone
2020
362
357
5
0
0
0
0
32
44
84
Ozone
2019
260
244
16
0
0
0
0
39
49
93
Ozone
2018
264
240
23
1
0
0
0
35
50
112
Ozone
2017
233
225
8
0
0
0
0
38
49
77
Ozone
2016
193
162
30
1
0
0
0
39
54
108
Ozone
2015
214
183
31
0
0
0
0
40
54
97
Ozone
2014
214
190
23
1
0
0
0
41
54
108
Ozone
2013
214
195
18
1
0
0
0
39
50
101
Ozone
2012
214
158
51
5
0
0
0
44
74
140
Ozone
2011
214
167
41
5
1
0
0
41
64
151
Ozone
2010
214
137
69
6
2
0
0
46
80
156
Ozone
2009
214
193
21
0
0
0
0
39
50
97
Ozone
2008
214
181
31
2
0
0
0
40
58
150
Ozone
2007
213
107
84
20
2
0
0
50
101
159
Ozone
2006
214
136
60
13
3
2
0
45
97
212
Ozone
2005
213
136
60
17
0
0
0
46
90
147
Ozone
2004
214
170
38
4
2
0
0
41
74
182
Ozone
2003
210
148
52
7
2
1
0
42
84
204
Ozone
2002
214
121
52
29
10
2
0
49
119
222
Ozone
2001
214
115
68
27
4
0
0
49
112
161
Ozone
2000
214
145
55
13
1
0
0
44
93
151
Ozone
1999
214
103
59
39
12
1
0
54
140
207
Ozone
1998
211
104
64
33
8
2
0
51
126
206
Ozone
1997
212
123
54
26
9
0
0
48
119
179
Ozone
1996
212
122
65
22
3
0
0
47
101
174
Ozone
1995
194
100
59
28
7
0
0
50
119
185
Ozone
1994
212
125
62
23
2
0
0
48
105
161
Ozone
1993
211
112
63
31
5
0
0
48
115
187
Ozone
1992
61
54
7
0
0
0
0
35
54
93
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 Virginia with a similar median AQI in 2025
