Daily Air Quality Index summaries from EPA monitors in Perry, Pennsylvania, 1980–2014.
94%
Good days in 2014
38
Median daily AQI, 2014
0
Days above 100 in 2014
302
Days with an AQI in 2014 (of 365)
In 2014, EPA reported a daily Air Quality Index (AQI) for Perry, Pennsylvania on 302 days. 284 of those days (94%) were in the Good range, and the median daily AQI was 38. That median is lower than the typical monitored county in Pennsylvania (median 52 across 38 counties), and lower than the typical monitored U.S. county (42). The main pollutant was ozone on 298 days. Across the years with fuller monitoring, the share of Good days rose: an average of 78% in 1980–1982 versus 90% in 2012–2014.
The most recent year with data for this county is 2014; EPA's files for 2015–2025 contain no row for it, which usually means its monitors stopped reporting.
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, 2014
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
298
99%
Nitrogen dioxide (NO₂)
4
1%
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
2014
302
284
18
0
0
0
0
38
48
80
Ozone
2013
365
329
36
0
0
0
0
36
50
93
Ozone
2012
366
318
42
6
0
0
0
34
54
126
Ozone
2011
357
312
43
2
0
0
0
32
54
112
Ozone
2010
353
304
44
5
0
0
0
30
58
133
Ozone
2009
358
339
18
1
0
0
0
24
46
101
Ozone
2008
350
293
49
6
2
0
0
31
64
159
Ozone
2007
347
287
52
8
0
0
0
32
64
122
Ozone
2006
363
309
48
6
0
0
0
25
67
143
Ozone
2005
363
235
108
19
1
0
0
39
87
156
Ozone
2004
365
269
94
2
0
0
0
34
69
108
Ozone
2003
364
261
93
7
3
0
0
37
74
166
Ozone
2002
362
237
90
28
6
1
0
39
100
205
Ozone
2001
363
234
95
25
9
0
0
40
93
197
Ozone
2000
365
265
92
6
2
0
0
35
71
169
Ozone
1999
355
266
55
23
11
0
0
30
100
190
Ozone
1998
356
274
52
22
8
0
0
32
93
179
Ozone
1997
353
294
41
13
5
0
0
31
71
187
Ozone
1996
360
303
45
12
0
0
0
33
64
150
Ozone
1995
362
301
40
18
3
0
0
31
77
169
Ozone
1994
365
287
50
24
4
0
0
32
87
177
Ozone
1993
363
288
44
23
8
0
0
34
93
187
Ozone
1992
359
318
31
10
0
0
0
30
54
133
Ozone
1991
363
269
55
26
13
0
0
35
105
190
Ozone
1990
364
302
42
18
2
0
0
33
67
179
Ozone
1989
363
312
41
9
1
0
0
33
67
154
Ozone
1988
331
252
31
14
26
8
0
32
151
229
Ozone
1987
339
264
47
16
12
0
0
34
93
185
Ozone
1986
321
271
33
17
0
0
0
32
77
150
Ozone
1985
359
283
53
19
4
0
0
36
87
190
Ozone
1984
347
299
37
8
3
0
0
31
61
169
Ozone
1983
347
265
43
29
9
1
0
35
105
205
Ozone
1982
325
262
47
9
5
2
0
34
77
222
Ozone
1981
242
199
32
6
5
0
0
33
84
177
Ozone
1980
222
157
36
20
6
3
0
41
112
212
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.
