Daily Air Quality Index summaries from EPA monitors in Catano, Puerto Rico, 1994–2025.
61%
Good days in 2025
45
Median daily AQI, 2025
0
Days above 100 in 2025
345
Days with an AQI in 2025 (of 365)
In 2025, EPA reported a daily Air Quality Index (AQI) for Catano, Puerto Rico on 345 days. 209 of those days (61%) were in the Good range, and the median daily AQI was 45. That median is higher than the typical monitored county in Puerto Rico (median 9 across 5 counties), and higher than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 328 days. Across the years with fuller monitoring, the share of Good days fell: an average of 95% in 1997–1999 versus 52% in 2023–2025.
Years with fewer than 120 monitored days (1994, 1995, 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
Fine particles (PM2.5)
328
95%
Coarse particles (PM10)
17
5%
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
345
209
136
0
0
0
0
45
62
99
PM2.5
2024
339
168
130
30
11
0
0
51
111
162
PM2.5
2023
209
96
101
10
2
0
0
52
91
155
PM2.5
2022
309
228
81
0
0
0
0
35
64
86
PM2.5
2021
300
151
136
12
1
0
0
50
80
151
PM2.5
2020
271
207
52
5
6
0
1
28
64
332
PM2.5
2019
347
194
142
10
1
0
0
45
89
173
PM2.5
2018
286
158
126
2
0
0
0
47
63
116
PM2.5
2017
253
190
61
2
0
0
0
33
60
116
PM2.5
2016
366
339
25
1
0
1
0
24
44
203
PM2.5
2015
365
337
27
1
0
0
0
19
46
139
PM10
2014
365
346
19
0
0
0
0
17
38
71
PM10
2013
365
358
7
0
0
0
0
19
32
60
PM10
2012
364
316
48
0
0
0
0
35
53
74
NO2
2011
360
357
3
0
0
0
0
21
34
55
Ozone
2010
363
340
23
0
0
0
0
23
41
98
Ozone
2009
364
348
16
0
0
0
0
21
36
92
Ozone
2008
366
357
9
0
0
0
0
22
37
74
Ozone
2007
365
338
26
1
0
0
0
22
44
122
PM10
2006
363
351
12
0
0
0
0
22
39
83
PM10
2005
363
336
27
0
0
0
0
24
43
80
PM10
2004
362
336
26
0
0
0
0
22
43
71
PM10
2003
350
327
23
0
0
0
0
23
44
69
PM10
2002
359
335
24
0
0
0
0
28
46
71
PM10
2001
357
347
10
0
0
0
0
27
43
65
PM10
2000
350
244
90
16
0
0
0
33
84
106
NO2
1999
321
317
4
0
0
0
0
22
31
87
Ozone
1998
280
262
17
1
0
0
0
22
39
103
NO2
1997
255
237
18
0
0
0
0
20
43
97
Ozone
1996
57
55
2
0
0
0
0
23
36
99
PM10
1995
60
58
2
0
0
0
0
19
35
55
PM10
1994
49
46
3
0
0
0
0
22
45
57
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 Puerto Rico with a similar median AQI in 2025
