Daily Air Quality Index summaries from EPA monitors in Gwinnett, Georgia, 1995–2025.
58%
Good days in 2025
47
Median daily AQI, 2025
0
Days above 100 in 2025
362
Days with an AQI in 2025 (of 365)
In 2025, EPA reported a daily Air Quality Index (AQI) for Gwinnett, Georgia on 362 days. 211 of those days (58%) were in the Good range, and the median daily AQI was 47. That median is about the same as the typical monitored county in Georgia (median 46 across 25 counties), and higher than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 246 days. Across the years with fuller monitoring, the share of Good days fell: an average of 54% in 1995–1997 versus 51% in 2023–2025.
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)
246
68%
Ozone
116
32%
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
362
211
151
0
0
0
0
47
66
92
PM2.5
2024
366
159
206
0
1
0
0
53
70
161
PM2.5
2023
365
186
172
7
0
0
0
50
74
140
PM2.5
2022
365
226
139
0
0
0
0
44
62
97
PM2.5
2021
324
173
149
2
0
0
0
49
67
108
PM2.5
2020
364
246
117
1
0
0
0
43
60
101
PM2.5
2019
355
154
199
2
0
0
0
52
71
112
PM2.5
2018
361
160
201
0
0
0
0
52
66
87
PM2.5
2017
356
208
148
0
0
0
0
48
64
97
PM2.5
2016
365
221
135
9
0
0
0
46
64
147
PM2.5
2015
365
215
146
3
1
0
0
45
64
154
PM2.5
2014
365
191
172
2
0
0
0
49
63
105
PM2.5
2013
365
211
153
1
0
0
0
47
63
112
PM2.5
2012
363
158
198
6
1
0
0
52
71
169
PM2.5
2011
364
121
226
16
1
0
0
56
84
156
PM2.5
2010
365
145
215
5
0
0
0
54
74
119
PM2.5
2009
365
158
203
4
0
0
0
54
71
147
PM2.5
2008
362
128
225
8
1
0
0
56
80
156
PM2.5
2007
355
89
227
32
7
0
0
62
105
185
PM2.5
2006
361
87
232
35
4
3
0
63
105
215
PM2.5
2005
361
98
235
28
0
0
0
60
97
150
PM2.5
2004
365
96
249
16
4
0
0
60
89
185
PM2.5
2003
309
139
148
17
4
1
0
53
90
203
Ozone
2002
263
140
88
28
7
0
0
48
115
195
Ozone
2001
187
109
66
10
1
1
0
44
93
203
Ozone
2000
256
106
104
35
9
2
0
59
122
219
Ozone
1999
212
91
66
40
13
2
0
64
143
234
Ozone
1998
185
71
60
28
20
6
0
67
164
212
Ozone
1997
197
109
57
27
4
0
0
48
112
177
Ozone
1996
215
124
59
23
8
1
0
48
112
203
Ozone
1995
219
106
79
24
9
1
0
51
115
204
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 Georgia with a similar median AQI in 2025
