Daily Air Quality Index summaries from EPA monitors in Ulster, New York, 1989–2012.
89%
Good days in 2012
36
Median daily AQI, 2012
1
Days above 100 in 2012
354
Days with an AQI in 2012 (of 366)
In 2012, EPA reported a daily Air Quality Index (AQI) for Ulster, New York on 354 days. 315 of those days (89%) were in the Good range, and the median daily AQI was 36. That median is lower than the typical monitored county in New York (median 40.5 across 32 counties), and lower than the typical monitored U.S. county (44). The main pollutant was ozone on 354 days. Across the years with fuller monitoring, the share of Good days rose: an average of 79% in 1991–1993 versus 89% in 2010–2012.
The most recent year with data for this county is 2012; EPA's files for 2013–2025 contain no row for it, which usually means its monitors stopped reporting.
Years with fewer than 120 monitored days (1989, 1990) 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, 2012
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
354
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
2012
354
315
38
1
0
0
0
36
51
101
Ozone
2011
360
330
26
4
0
0
0
38
50
122
Ozone
2010
363
317
44
2
0
0
0
37
54
115
Ozone
2009
362
336
25
1
0
0
0
36
48
108
Ozone
2008
356
329
25
2
0
0
0
33
48
147
Ozone
2007
360
315
39
6
0
0
0
36
58
140
Ozone
2006
360
318
37
5
0
0
0
36
54
129
Ozone
2005
355
302
42
11
0
0
0
40
58
147
Ozone
2004
362
317
37
8
0
0
0
37
54
143
Ozone
2003
362
303
45
11
3
0
0
39
67
172
Ozone
2002
361
291
51
18
1
0
0
38
77
159
Ozone
2001
364
298
47
17
2
0
0
39
77
164
Ozone
2000
360
312
38
9
1
0
0
35
58
164
Ozone
1999
310
239
56
12
3
0
0
41
71
177
Ozone
1998
350
276
52
21
1
0
0
38
77
154
Ozone
1997
365
304
46
11
4
0
0
37
67
159
Ozone
1996
365
307
47
9
2
0
0
37
64
164
Ozone
1995
359
302
43
11
3
0
0
36
67
159
Ozone
1994
363
280
67
16
0
0
0
39
80
143
Ozone
1993
363
276
60
19
8
0
0
40
90
197
Ozone
1992
344
294
36
7
7
0
0
35
64
169
Ozone
1991
341
255
55
20
11
0
0
41
97
182
Ozone
1990
58
58
0
0
0
0
0
17
35
44
PM10
1989
30
29
1
0
0
0
0
26
43
53
PM10
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 2012
