Daily Air Quality Index summaries from EPA monitors in Hamilton, New York, 1991–2025.
97%
Good days in 2025
34
Median daily AQI, 2025
0
Days above 100 in 2025
355
Days with an AQI in 2025 (of 365)
In 2025, EPA reported a daily Air Quality Index (AQI) for Hamilton, New York on 355 days. 345 of those days (97%) were in the Good range, and the median daily AQI was 34. That median is about the same as the typical monitored county in New York (median 36 across 27 counties), and lower than the typical monitored U.S. county (40). The main pollutant was ozone on 355 days. Across the years with fuller monitoring, the share of Good days rose: an average of 91% in 1991–1993 versus 97% 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
Ozone
355
100%
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
355
345
10
0
0
0
0
34
44
87
Ozone
2024
348
340
8
0
0
0
0
33
44
74
Ozone
2023
354
337
17
0
0
0
0
33
46
90
Ozone
2022
350
345
5
0
0
0
0
34
43
71
Ozone
2021
358
343
15
0
0
0
0
33
44
100
Ozone
2020
357
354
3
0
0
0
0
34
44
54
Ozone
2019
323
321
2
0
0
0
0
35
44
54
Ozone
2018
352
341
11
0
0
0
0
33
45
97
Ozone
2017
358
341
17
0
0
0
0
34
45
87
Ozone
2016
324
309
13
2
0
0
0
34
44
112
Ozone
2015
359
342
17
0
0
0
0
33
46
90
Ozone
2014
358
347
11
0
0
0
0
33
44
84
Ozone
2013
357
338
19
0
0
0
0
34
46
84
Ozone
2012
349
310
36
3
0
0
0
34
51
150
Ozone
2011
351
335
15
1
0
0
0
35
46
101
Ozone
2010
359
331
27
1
0
0
0
36
49
105
Ozone
2009
361
332
27
2
0
0
0
34
47
105
Ozone
2008
362
327
32
3
0
0
0
34
50
122
Ozone
2007
359
320
31
8
0
0
0
35
51
140
Ozone
2006
346
316
28
2
0
0
0
35
50
133
Ozone
2005
351
314
30
7
0
0
0
36
51
150
Ozone
2004
353
314
37
2
0
0
0
38
51
140
Ozone
2003
348
310
32
4
2
0
0
37
54
161
Ozone
2002
356
306
35
12
3
0
0
35
61
169
Ozone
2001
363
310
42
9
2
0
0
37
61
156
Ozone
2000
360
329
27
3
1
0
0
35
49
185
Ozone
1999
358
295
52
11
0
0
0
37
64
150
Ozone
1998
361
308
44
8
1
0
0
36
61
151
Ozone
1997
354
318
25
10
1
0
0
34
51
154
Ozone
1996
357
338
18
1
0
0
0
34
48
147
Ozone
1995
354
319
27
6
2
0
0
34
50
185
Ozone
1994
354
319
29
6
0
0
0
35
50
119
Ozone
1993
348
314
31
2
1
0
0
32
50
161
Ozone
1992
357
325
24
7
1
0
0
33
49
159
Ozone
1991
144
132
8
4
0
0
0
31
48
147
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 New York with a similar median AQI in 2025
