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Athens, TN Air Quality

EPA monitor data through 2025 · Updated September 02, 2026 · Methods

In 2025, Athens, TN recorded 0 days above an Air Quality Index of 100, the level at which EPA begins warning sensitive groups, out of 357 days with monitoring data. The rest of the year was 279 Good days and 78 Moderate days. Under the AQI rules that applied before 2013, the same air would have scored 0 days. Since 2000, unhealthy days are 100% lower on a consistent definition.

Unhealthy days, 2025

AQI above 100

Same air, pre-2013 rules

for comparison with older reports

Good-air days

279

AQI 50 or below

Days monitored

357

full year

Unhealthy days by year, scored two ways

EPA changed what an AQI of 100 means in 2013 and again in 2015, so a count published before those changes is not comparable to one published after. Each panel below applies a single fixed rulebook to every year, so each is internally consistent. Why this matters.

Scored by today's rules

Scored by the pre-2013 rules

Faded columns mark years with fewer than 300 monitored days, where the count is not comparable.

What 2025 looked like

Air quality category	Days	Share of days with an AQI
Good	279	78%
Moderate	78	22%
Unhealthy for sensitive groups	0	0%
Unhealthy or worse	0	0%

Median AQI 37 · 90th-percentile AQI 55 · worst day 71. Scored under current rules, out of 357 days with an AQI.

Statewide context

Athens, TN sits in Tennessee.

Days in each air quality category, by year

How many days fell in each AQI category, for every year with an AQI on record. Categories are scored under EPA's current breakpoints. A year with fewer than 300 days is marked, because a short year lowers every count for reasons that have nothing to do with the air.

Year	Good	Moderate	Unhealthy for sensitive groups	Unhealthy or worse	Days with an AQI
2000	271	89	5	0	365
2001	267	89	2	0	358
2002	276	85	1	0	362
2003	256	66	2	0	324
2004	277	86	0	0	363
2005	276	84	1	0	361
2006	263	84	2	0	349
2007	269	93	3	0	365
2008	355	2	0	0	357
2009	362	0	0	0	362
2010	358	1	0	0	359
2011	359	1	0	0	360
2012 (partial)	234	0	0	0	234
2013 (partial)	59	41	0	0	100
2014 (partial)	211	69	0	0	280
2015 (partial)	72	38	0	0	110
2016 (partial)	76	42	0	1	119
2017 (partial)	142	79	0	0	221
2018	246	110	0	0	356
2019	239	118	0	0	357
2020	280	78	0	0	358
2021	250	110	0	0	360
2022	233	124	0	0	357
2023	238	115	2	0	355
2024	281	75	0	0	356
2025	279	78	0	0	357

Good is AQI 0–50, Moderate 51–100, Unhealthy for sensitive groups 101–150. “Unhealthy or worse” combines the Unhealthy, Very Unhealthy and Hazardous categories, which are shown together because most areas record too few of each to report separately. The four columns sum to the last one by construction. These counts exclude sulphur dioxide, following EPA, which drops SO₂ from county and metro summaries because it is too localized to describe a whole area.

The full series

The same years scored two ways, with the pollutant that drove the days above 100. EPA's files record which pollutant set each day's AQI; they do not attribute days to wildfire smoke, so no column here claims to.

Year	Unhealthy days, current rules	Of which fine particles	Pre-2013 rules	Days monitored
2000	5	5	2	365
2001	2	2	1	365
2002	1	1	0	365
2003	2	1	2	324
2004	0	0	0	363
2005	1	1	0	363
2006	2	2	0	350
2007	3	3	1	365
2008	0	0	0	357
2009	0	0	0	362
2010	0	0	0	363
2011	0	0	0	360
2012	0	0	0	234
2013	0	0	0	100
2014	0	0	0	280
2015	0	0	0	110
2016	1	1	1	119
2017	0	0	0	221
2018	0	0	0	356
2019	0	0	0	357
2020	0	0	0	358
2021	0	0	0	360
2022	0	0	0	357
2023	2	2	1	355
2024	0	0	0	356
2025	0	0	0	357

Sources

EPA AirData daily monitor files, recomputed under both breakpoint tables. Methods and validation.
Download the full dataset for every state and metro.