Daily Air Quality Index summaries from EPA monitors in Bronx, New York, 1980–2025.
59%
Good days in 2025
45
Median daily AQI, 2025
8
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 Bronx, New York on 365 days. 216 of those days (59%) were in the Good range, and the median daily AQI was 45. That median is higher than the typical monitored county in New York (median 36 across 27 counties), and higher than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 223 days. Across the years with fuller monitoring, the share of Good days fell: an average of 75% in 1980–1982 versus 60% in 2023–2025.
Years with fewer than 120 monitored days (1989) 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)
223
61%
Ozone
112
31%
Nitrogen dioxide (NO₂)
30
8%
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
216
141
8
0
0
0
45
67
143
PM2.5
2024
366
246
118
2
0
0
0
42
67
150
PM2.5
2023
365
197
159
5
3
1
0
47
69
253
PM2.5
2022
365
225
139
1
0
0
0
44
61
101
PM2.5
2021
365
214
143
7
1
0
0
47
68
156
PM2.5
2020
366
229
136
1
0
0
0
45
64
108
PM2.5
2019
365
212
150
3
0
0
0
46
66
115
PM2.5
2018
365
229
127
9
0
0
0
44
65
150
PM2.5
2017
365
241
122
2
0
0
0
44
62
136
PM2.5
2016
366
226
136
4
0
0
0
45
65
140
PM2.5
2015
365
177
182
6
0
0
0
51
73
136
PM2.5
2014
365
179
182
4
0
0
0
51
68
133
PM2.5
2013
365
171
187
7
0
0
0
52
71
119
PM2.5
2012
366
152
201
13
0
0
0
53
72
133
PM2.5
2011
365
112
243
9
1
0
0
56
77
161
PM2.5
2010
365
129
225
11
0
0
0
54
77
136
PM2.5
2009
365
125
232
8
0
0
0
55
78
147
PM2.5
2008
366
90
264
11
1
0
0
58
82
151
PM2.5
2007
365
110
238
17
0
0
0
57
88
150
PM2.5
2006
365
145
206
10
4
0
0
55
86
185
PM2.5
2005
365
102
243
19
1
0
0
59
87
179
PM2.5
2004
366
100
256
9
1
0
0
57
83
154
PM2.5
2003
365
101
249
13
2
0
0
59
87
187
PM2.5
2002
365
102
234
21
8
0
0
58
96
200
PM2.5
2001
356
91
240
23
2
0
0
61
92
156
PM2.5
2000
366
94
252
18
2
0
0
59
90
195
PM2.5
1999
365
184
160
13
6
2
0
50
85
201
NO2
1998
365
203
151
10
1
0
0
48
86
187
NO2
1997
364
210
132
17
4
1
0
46
77
205
NO2
1996
351
201
136
10
4
0
0
47
81
172
NO2
1995
365
209
133
12
9
2
0
47
81
210
NO2
1994
365
174
177
13
1
0
0
51
80
156
NO2
1993
291
164
116
9
2
0
0
48
82
166
NO2
1992
305
242
57
6
0
0
0
33
65
122
Ozone
1991
345
205
136
4
0
0
0
45
78
112
NO2
1990
285
150
121
13
1
0
0
49
85
164
NO2
1989
38
33
5
0
0
0
0
27
54
55
PM10
1988
141
106
33
2
0
0
0
40
63
106
NO2
1987
328
173
145
10
0
0
0
49
85
110
NO2
1986
320
192
114
14
0
0
0
46
86
125
NO2
1985
353
222
111
20
0
0
0
43
86
132
NO2
1984
331
207
109
15
0
0
0
42
79
127
NO2
1983
350
191
135
24
0
0
0
48
93
112
NO2
1982
243
127
106
10
0
0
0
49
82
118
NO2
1981
164
142
20
2
0
0
0
28
56
103
CO
1980
303
260
42
1
0
0
0
25
57
117
CO
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 New York with a similar median AQI in 2025
