Carter County, Oklahoma air quality history

Daily Air Quality Index summaries from EPA monitors in Carter, Oklahoma, 1989–2025.

82%

Good days in 2025

Median daily AQI, 2025

Days above 100 in 2025

343

Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Carter, Oklahoma on 343 days. 280 of those days (82%) were in the Good range, and the median daily AQI was 32. That median is lower than the typical monitored county in Oklahoma (median 44 across 19 counties), and lower than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 343 days. Across the years with fuller monitoring, the share of Good days rose: an average of 55% in 2001–2003 versus 65% in 2023–2025.

Years with fewer than 120 monitored days (1996, 1997, 1999, 2000, 2005, 2013…) 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)	343	100%

Year-by-year data

Annual AQI summary by year
Year	Days with AQI	Good	Moderate	Unhealthy for Sensitive Groups	Unhealthy	Median AQI	90th pct.	Max AQI	Main pollutant
2025	343	280	62	0	1	32	55	155	PM2.5
2024	363	217	132	14	0	48	74	143	Ozone
2023	344	189	138	17	0	48	87	136	Ozone
2022	343	254	88	0	1	37	56	160	PM2.5
2021	316	186	129	1	0	46	61	118	PM2.5
2020	345	201	143	1	0	47	67	147	PM2.5
2019	365	228	137	0	0	46	61	97	PM2.5
2018	356	227	127	2	0	41	60	128	PM2.5
2017	310	197	113	0	0	43	58	80	PM2.5
2016	298	241	54	3	0	42	61	129	Ozone
2013	62	39	23	0	0	44	60	72	PM2.5
2012	348	131	199	18	0	55	87	147	PM2.5
2011	333	116	180	34	3	57	105	177	Ozone
2010	357	235	122	0	0	39	59	74	PM2.5
2009	331	182	147	0	2	46	62	176	PM2.5
2008	274	193	74	7	0	45	77	122	Ozone
2007	270	174	80	15	1	46	93	172	Ozone
2005	57	29	28	0	0	49	64	86	PM2.5
2004	281	183	90	8	0	43	71	133	Ozone
2003	277	137	118	22	0	51	93	150	Ozone
2002	302	192	91	16	3	44	84	179	Ozone
2001	256	133	96	24	3	50	101	172	Ozone
2000	111	55	56	0	0	51	65	83	PM2.5
1999	21	9	12	0	0	54	71	78	PM2.5
1997	24	23	1	0	0	26	43	53	PM10
1996	51	50	1	0	0	22	41	55	PM10
1995	55	53	2	0	0	18	44	54	PM10
1994	36	35	1	0	0	21	43	52	PM10
1993	54	52	2	0	0	22	39	57	PM10
1992	55	53	2	0	0	24	41	63	PM10
1991	53	53	0	0	0	22	40	46	PM10
1990	57	54	3	0	0	21	37	52	PM10
1989	33	33	0	0	0	24	38	45	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 Oklahoma with a similar median AQI in 2025

All monitored counties in Oklahoma

Source: U.S. EPA AirData, “Annual AQI by County” files for 1989–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem