Daily Air Quality Index summaries from EPA monitors in Cecil, Maryland, 1980–2025.
80%
Good days in 2025
41
Median daily AQI, 2025
2
Days above 100 in 2025
361
Days with an AQI in 2025 (of 365)
In 2025, EPA reported a daily Air Quality Index (AQI) for Cecil, Maryland on 361 days. 288 of those days (80%) were in the Good range, and the median daily AQI was 41. That median is about the same as the typical monitored county in Maryland (median 39.5 across 16 counties), and about the same as the typical monitored U.S. county (40). The main pollutant was ozone on 195 days. Across the years with fuller monitoring, the share of Good days rose: an average of 64% in 1992–1994 versus 73% in 2023–2025.
Years with fewer than 120 monitored days (1980, 1990, 1991) 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
195
54%
Fine particles (PM2.5)
166
46%
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
361
288
71
2
0
0
0
41
60
129
Ozone
2024
360
236
121
3
0
0
0
44
63
126
PM2.5
2023
360
266
88
2
4
0
0
42
64
190
Ozone
2022
361
267
93
1
0
0
0
43
58
101
PM2.5
2021
358
235
119
4
0
0
0
44
65
118
PM2.5
2020
357
309
48
0
0
0
0
38
54
97
Ozone
2019
361
265
93
3
0
0
0
42
61
150
Ozone
2018
358
207
144
7
0
0
0
47
63
129
PM2.5
2017
360
222
130
7
1
0
0
45
65
161
PM2.5
2016
359
209
140
9
1
0
0
47
67
154
PM2.5
2015
358
180
173
4
1
0
0
50
75
187
PM2.5
2014
347
193
149
5
0
0
0
47
67
150
PM2.5
2013
357
188
164
5
0
0
0
49
71
143
PM2.5
2012
360
180
156
19
5
0
0
51
87
172
PM2.5
2011
357
167
178
6
6
0
0
52
79
177
PM2.5
2010
353
168
163
20
2
0
0
52
89
161
PM2.5
2009
355
162
185
8
0
0
0
52
72
143
PM2.5
2008
296
110
162
20
4
0
0
55
93
195
PM2.5
2007
258
120
105
28
4
1
0
53
115
221
Ozone
2006
248
129
91
23
5
0
0
50
105
190
Ozone
2005
262
128
105
20
8
1
0
51
105
206
Ozone
2004
255
142
93
18
2
0
0
47
93
182
Ozone
2003
230
129
83
13
3
2
0
47
97
212
Ozone
2002
258
130
86
25
12
5
0
50
133
221
Ozone
2001
263
122
102
23
15
1
0
53
119
212
Ozone
2000
261
122
112
9
14
4
0
52
101
229
Ozone
1999
237
137
51
29
15
5
0
45
140
222
Ozone
1998
231
123
55
35
17
1
0
49
143
227
Ozone
1997
235
153
48
16
13
5
0
43
140
234
Ozone
1996
234
144
59
21
9
1
0
44
115
210
Ozone
1995
224
127
53
28
11
5
0
47
136
229
Ozone
1994
234
146
48
31
8
1
0
45
119
204
Ozone
1993
231
139
44
28
16
4
0
44
140
223
Ozone
1992
231
160
45
18
8
0
0
41
101
187
Ozone
1991
22
22
0
0
0
0
0
19
33
39
PM10
1990
45
44
1
0
0
0
0
20
33
51
PM10
1980
67
16
14
19
10
8
0
105
201
218
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 Maryland with a similar median AQI in 2025
