Athens County, Ohio air quality history

Daily Air Quality Index summaries from EPA monitors in Athens, Ohio, 1991–2025.

83%

Good days in 2025

Median daily AQI, 2025

Days above 100 in 2025

361

Days with an AQI in 2025 (of 365)

In 2025, EPA reported a daily Air Quality Index (AQI) for Athens, Ohio on 361 days. 301 of those days (83%) were in the Good range, and the median daily AQI was 31. That median is lower than the typical monitored county in Ohio (median 43 across 36 counties), and lower than the typical monitored U.S. county (40). The main pollutant was fine particles (PM2.5) on 361 days. Across the years with fuller monitoring, the share of Good days rose: an average of 75% in 2007–2009 versus 86% in 2023–2025.

Years with fewer than 120 monitored days (2016, 2017, 2018, 2020, 2021, 2022…) 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)	361	100%

Year-by-year data

Annual AQI summary by year
Year	Days with AQI	Good	Moderate	Unhealthy for Sensitive Groups	Unhealthy	Very Unhealthy	Median AQI	90th pct.	Max AQI	Main pollutant
2025	361	301	60	0	0	0	31	54	75	PM2.5
2024	364	330	34	0	0	0	28	49	64	PM2.5
2023	244	208	35	0	1	0	31	54	157	PM2.5
2022	119	107	12	0	0	0	27	51	67	PM2.5
2021	113	91	22	0	0	0	27	55	77	PM2.5
2020	86	73	13	0	0	0	32	52	65	PM2.5
2019	120	99	21	0	0	0	33	53	61	PM2.5
2018	94	75	19	0	0	0	37	55	62	PM2.5
2017	59	46	13	0	0	0	34	54	61	PM2.5
2016	60	52	8	0	0	0	36	53	61	PM2.5
2015	57	36	21	0	0	0	38	59	71	PM2.5
2014	56	36	20	0	0	0	38	59	70	PM2.5
2013	57	37	20	0	0	0	44	58	69	PM2.5
2012	55	34	21	0	0	0	45	61	72	PM2.5
2011	347	278	65	4	0	0	31	64	115	Ozone
2010	361	290	68	3	0	0	33	64	119	Ozone
2009	365	296	68	1	0	0	32	58	108	Ozone
2008	364	281	80	3	0	0	40	67	115	Ozone
2007	360	239	99	21	1	0	41	90	151	Ozone
2006	53	23	30	0	0	0	53	71	98	PM2.5
2005	61	19	38	3	0	1	56	91	213	PM2.5
2004	67	28	38	1	0	0	53	77	124	PM2.5
2003	109	44	64	1	0	0	53	76	110	PM2.5
2002	112	45	66	1	0	0	55	74	104	PM2.5
2001	114	49	64	1	0	0	54	76	114	PM2.5
2000	98	40	58	0	0	0	54	76	94	PM2.5
1999	108	32	74	2	0	0	56	75	127	PM2.5
1998	59	59	0	0	0	0	12	31	38	PM10
1997	56	56	0	0	0	0	18	28	35	PM10
1996	58	58	0	0	0	0	16	22	45	PM10
1995	59	59	0	0	0	0	17	31	46	PM10
1994	56	54	2	0	0	0	16	31	52	PM10
1993	61	61	0	0	0	0	16	35	46	PM10
1992	57	56	1	0	0	0	19	31	52	PM10
1991	20	20	0	0	0	0	19	40	47	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 Ohio with a similar median AQI in 2025

All monitored counties in Ohio

Source: U.S. EPA AirData, “Annual AQI by County” files for 1991–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem