Daily Air Quality Index summaries from EPA monitors in Ottawa, Oklahoma, 1999–2025.
54%
Good days in 2025
49
Median daily AQI, 2025
2
Days above 100 in 2025
365
Days with an AQI in 2025 (of 365)
In 2025, EPA reported a daily Air Quality Index (AQI) for Ottawa, Oklahoma on 365 days. 196 of those days (54%) were in the Good range, and the median daily AQI was 49. That median is higher than the typical monitored county in Oklahoma (median 44 across 19 counties), and higher than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 259 days. Across the years with fuller monitoring, the share of Good days fell: an average of 67% in 2001–2003 versus 47% in 2023–2025.
Years with fewer than 120 monitored days (1999, 2000) 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)
259
71%
Ozone
89
24%
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
365
196
167
1
0
0
1
49
66
305
PM2.5
2024
366
181
184
0
0
1
0
51
70
288
PM2.5
2023
364
141
215
7
1
0
0
54
76
162
PM2.5
2022
365
151
203
6
4
1
0
53
74
238
PM2.5
2021
365
90
258
14
3
0
0
59
87
169
PM2.5
2020
352
202
148
1
1
0
0
46
65
154
PM2.5
2019
363
222
140
1
0
0
0
45
62
104
PM2.5
2018
365
156
208
1
0
0
0
52
66
107
PM2.5
2017
365
175
190
0
0
0
0
51
62
94
PM2.5
2016
366
206
160
0
0
0
0
47
61
81
PM2.5
2015
364
186
178
0
0
0
0
50
62
89
PM2.5
2014
364
185
178
1
0
0
0
50
66
118
PM2.5
2013
364
215
148
1
0
0
0
46
65
108
PM2.5
2012
363
143
203
15
2
0
0
53
77
161
PM2.5
2011
365
152
197
16
0
0
0
53
80
143
PM2.5
2010
361
169
189
3
0
0
0
51
71
119
PM2.5
2009
343
164
177
2
0
0
0
51
65
115
PM2.5
2008
364
175
189
0
0
0
0
51
67
97
PM2.5
2007
364
160
197
7
0
0
0
53
77
115
PM2.5
2006
365
252
101
11
1
0
0
40
80
151
Ozone
2005
365
230
120
15
0
0
0
44
87
140
Ozone
2004
365
275
82
7
1
0
0
41
69
169
Ozone
2003
364
231
113
20
0
0
0
44
80
140
Ozone
2002
363
269
82
12
0
0
0
39
80
129
Ozone
2001
365
237
102
25
1
0
0
44
97
151
Ozone
2000
55
20
34
1
0
0
0
56
76
110
PM2.5
1999
18
7
11
0
0
0
0
54
75
88
PM2.5
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 Oklahoma with a similar median AQI in 2025
