Daily Air Quality Index summaries from EPA monitors in Franklin, Pennsylvania, 1996–2025.
92%
Good days in 2025
37
Median daily AQI, 2025
0
Days above 100 in 2025
295
Days with an AQI in 2025 (of 365)
In 2025, EPA reported a daily Air Quality Index (AQI) for Franklin, Pennsylvania on 295 days. 270 of those days (92%) were in the Good range, and the median daily AQI was 37. That median is lower than the typical monitored county in Pennsylvania (median 40 across 38 counties), and lower than the typical monitored U.S. county (40). The main pollutant was ozone on 295 days. Across the years with fuller monitoring, the share of Good days rose: an average of 41% in 1997–1999 versus 91% in 2023–2025.
EPA did not report an AQI for every day of 2025 here (295 of 365 days). Figures describe monitored days only; seasonal monitoring (for example, ozone measured only in warmer months) can make a county look cleaner or dirtier than a full-year record would.
Years with fewer than 120 monitored days (1996) 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
295
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
295
270
25
0
0
0
0
37
49
87
Ozone
2024
327
305
22
0
0
0
0
35
49
90
Ozone
2023
301
267
32
2
0
0
0
39
51
133
Ozone
2022
237
225
12
0
0
0
0
39
47
84
Ozone
2021
288
274
14
0
0
0
0
35
47
77
Ozone
2020
363
363
0
0
0
0
0
32
42
50
Ozone
2019
341
324
17
0
0
0
0
36
48
80
Ozone
2018
353
343
10
0
0
0
0
32
44
74
Ozone
2017
358
354
4
0
0
0
0
33
45
67
Ozone
2016
337
325
12
0
0
0
0
33
44
74
Ozone
2015
359
340
19
0
0
0
0
34
47
77
Ozone
2014
337
311
26
0
0
0
0
38
49
87
Ozone
2013
344
279
61
4
0
0
0
40
61
115
Ozone
2012
273
213
59
1
0
0
0
40
67
115
Ozone
2011
180
150
29
1
0
0
0
41
64
112
Ozone
2010
210
150
58
2
0
0
0
45
77
122
Ozone
2009
208
196
12
0
0
0
0
37
47
84
Ozone
2008
204
156
39
9
0
0
0
43
77
115
Ozone
2007
212
122
72
18
0
0
0
48
97
129
Ozone
2006
213
172
40
1
0
0
0
42
61
101
Ozone
2005
204
139
57
8
0
0
0
45
87
119
Ozone
2004
197
144
49
4
0
0
0
44
80
119
Ozone
2003
192
128
58
4
2
0
0
46
77
174
Ozone
2002
203
85
59
33
24
2
0
67
154
203
Ozone
2001
204
84
65
41
14
0
0
64
140
182
Ozone
2000
207
119
60
25
3
0
0
47
108
179
Ozone
1999
210
83
68
41
17
1
0
64
147
203
Ozone
1998
211
75
73
42
19
2
0
67
150
203
Ozone
1997
210
101
64
41
4
0
0
54
126
197
Ozone
1996
116
65
37
11
3
0
0
48
105
177
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 Pennsylvania with a similar median AQI in 2025
