Which county in Oklahoma has the best air quality?

Based on 2023 EPA AQS data, Grant County had the best air quality in Oklahoma with a median AQI of 32 and 92 good-air days.

2024 monitoring year Public dataset EPA AQS

Oklahoma Air Quality Rankings

Compiled by PlainEnviro Editorial, Environmental Data Editorial Team · July 13, 2026

County-level AQI rollup using EPA Air Quality System monitor records. Refreshed as new EPA AQS data lands.

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County-by-county air quality data for Oklahoma based on EPA AQS annual AQI readings. Data covers 24 monitored counties for 2023.

Oklahoma (2023): 24 counties monitored. State average median AQI: 46 (national average: 38.8). 65% of monitored days rated "Good." Most unhealthy air: Kay County (1 days above AQI 100).

Oklahoma air quality on this page is drawn from the EPA Air Quality System (AQS), which aggregates daily readings from federal, state, tribal, and local monitors into annual summaries per county. The current dataset covers 24 Oklahoma counties with at least ten days of valid AQI readings in 2023, out of the state's total monitored counties.

The state-average median AQI across those counties is 46, compared with a national average of 38.8 in the same reporting period. On average, 65% of monitored days fell into the "Good" AQI bucket (0–50). The heaviest burden of unhealthy days lands on Kay County (1 day above AQI 100), while Grant County records the cleanest air with a median AQI of 32.

AQI values translate ambient concentrations of pollutants (ozone, PM2.5, PM10, NO₂, SO₂, CO) onto a single 0–500 scale with six health-based bands. A low median AQI reflects typical daily conditions; peak values matter separately because short-term exposure drives most acute health effects. Counties without monitors are not "clean" - they are simply unmeasured by EPA AQS. For site-specific exposure guidance, check AirNow.gov alongside the county detail links below.

Counties with Data

State Avg Median AQI

National Avg Median AQI

38.8

Avg Good Days %

65%

Which Oklahoma counties have the worst air quality?

Ranked by median AQI (higher = worse). Click a county for full environmental data.

#	County	Median AQI	Good Days	Good %	Unhealthy Days	Peak AQI
1	Nowata	54	132	39%	0	140
2	Oklahoma	52	172	47%	0	147
3	Cleveland	51	177	49%	0	126
4	Tulsa	51	177	48%	0	140
5	Ottawa	51	181	49%	1	288
6	Carter	48	217	60%	0	143
7	Pittsburg	48	198	55%	0	105
8	Dewey	47	221	60%	0	112
9	Washington	47	182	57%	1	156
10	Adair	47	209	57%	0	138
11	Mcclain	46	172	64%	0	133
12	Love	45	196	70%	0	150
13	Canadian	44	204	76%	0	119
14	Osage	44	223	77%	0	112
15	Creek	44	202	76%	1	179
16	Sequoyah	44	252	69%	0	97
17	Johnston	44	192	75%	0	119
18	Kiowa	44	185	72%	0	115
19	Comanche	43	242	67%	1	339
20	Pontotoc	43	207	72%	0	101
21	Jefferson	42	247	81%	0	108
22	Kay	42	223	63%	1	193
23	Mayes	40	261	90%	0	112
24	Grant	32	92	83%	0	86

Frequently Asked Questions

What is the air quality like in Oklahoma?

In 2023, Oklahoma had an average median AQI of 46 across 24 monitored counties, with 65% of monitored days rated "Good" (AQI 0–50). The national average median AQI is 38.8.

Which county in Oklahoma has the worst air quality?

Based on 2023 EPA AQS data, Kay County had the most unhealthy air days in Oklahoma - 1 days above AQI 100, with a median AQI of 42.

Explore More

National AQI Rankings → Oklahoma Full Profile → Oklahoma Water Quality →

About This Data

Air quality data is from the EPA Air Quality System (AQS), Annual AQI by County dataset. Counties with fewer than 10 monitored days are excluded. "Unhealthy days" counts days with AQI above 100 (Unhealthy for Sensitive Groups or worse). All data is for 2023.

Source: U.S. Environmental Protection Agency, Air Quality System (AQS) U.S. Environmental Protection Agency, Air Quality System (AQS)

Read our methodology - how this data is sourced, computed, and verified.

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Data sourced from the U.S. Environmental Protection Agency (EPA). See our methodology for details. Retrieved and formatted by PlainEnviro Editorial