Daily Air Quality Index summaries from EPA monitors in Hancock, Mississippi, 1987–2025.
70%
Good days in 2025
43
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 Hancock, Mississippi on 365 days. 256 of those days (70%) were in the Good range, and the median daily AQI was 43. That median is about the same as the typical monitored county in Mississippi (median 43 across 10 counties), and higher than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 248 days. Across the years with fuller monitoring, the share of Good days held roughly steady: an average of 62% in 1987–1989 versus 63% in 2023–2025.
Years with fewer than 120 monitored days (2006) 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)
248
68%
Ozone
117
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
365
256
109
0
0
0
0
43
58
84
PM2.5
2024
357
245
112
0
0
0
0
43
60
87
PM2.5
2023
364
188
175
1
0
0
0
50
67
112
PM2.5
2022
359
238
121
0
0
0
0
44
58
89
PM2.5
2021
360
225
135
0
0
0
0
45
60
97
PM2.5
2020
351
217
134
0
0
0
0
45
59
90
PM2.5
2019
365
263
102
0
0
0
0
43
58
80
PM2.5
2018
363
257
105
1
0
0
0
41
59
102
PM2.5
2017
278
225
53
0
0
0
0
40
57
77
Ozone
2016
277
234
43
0
0
0
0
40
55
90
Ozone
2015
276
212
64
0
0
0
0
38
58
85
Ozone
2014
243
218
23
2
0
0
0
37
51
112
Ozone
2013
241
218
23
0
0
0
0
38
50
87
Ozone
2012
228
197
29
2
0
0
0
38
61
108
Ozone
2011
280
195
83
2
0
0
0
44
64
119
Ozone
2010
285
190
94
1
0
0
0
44
67
108
Ozone
2009
283
215
67
1
0
0
0
41
59
119
Ozone
2006
41
4
37
0
0
0
0
61
76
94
PM2.5
2005
282
117
151
14
0
0
0
55
84
136
Ozone
2004
359
252
97
10
0
0
0
40
74
122
Ozone
2003
364
252
95
12
5
0
0
40
77
174
Ozone
2002
356
270
77
8
1
0
0
38
67
159
Ozone
2001
363
253
95
13
2
0
0
41
77
161
Ozone
2000
362
204
114
39
5
0
0
46
108
195
Ozone
1999
359
196
114
42
7
0
0
46
115
172
Ozone
1998
268
176
63
24
5
0
0
44
105
187
Ozone
1997
210
128
57
24
1
0
0
48
101
156
Ozone
1996
255
178
64
11
2
0
0
43
93
164
Ozone
1995
266
157
68
37
4
0
0
47
119
172
Ozone
1994
268
155
81
25
7
0
0
48
108
200
Ozone
1993
258
175
66
16
1
0
0
45
90
161
Ozone
1992
267
196
58
9
4
0
0
42
87
177
Ozone
1991
271
210
51
8
2
0
0
40
71
169
Ozone
1990
268
172
75
17
4
0
0
45
93
166
Ozone
1989
259
164
66
25
4
0
0
45
105
190
Ozone
1988
252
164
55
23
10
0
0
44
112
177
Ozone
1987
261
151
75
31
4
0
0
46
115
190
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 Mississippi with a similar median AQI in 2025
