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Salem, OH Air Quality

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

2025 coverage is partial so far: 61 days of monitoring data have been reported. Counts for 2025 will grow as EPA processes the rest of the year.

In 2025, Salem, OH recorded 0 days above an Air Quality Index of 100, the level at which EPA begins warning sensitive groups, out of 61 days with monitoring data. The rest of the year was 61 Good days and 0 Moderate days. Under the AQI rules that applied before 2013, the same air would have scored 0 days.

Unhealthy days, 2025

AQI above 100

Same air, pre-2013 rules

for comparison with older reports

Good-air days

AQI 50 or below

Days monitored

partial coverage

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	61	100%
Moderate	0	0%
Unhealthy for sensitive groups	0	0%
Unhealthy or worse	0	0%

Median AQI 12 · 90th-percentile AQI 22 · worst day 31. Scored under current rules, out of 61 days with an AQI.

Statewide context

Salem, OH sits in Ohio.

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	Days with an AQI
2000 (partial)	38	9	47
2001 (partial)	16	1	17
2002 (partial)	17	1	18
2003 (partial)	52	9	61
2004 (partial)	54	7	61
2005 (partial)	55	6	61
2006 (partial)	58	3	61
2007 (partial)	56	3	59
2008 (partial)	59	2	61
2009 (partial)	60	1	61
2010 (partial)	59	2	61
2011 (partial)	61	0	61
2012 (partial)	61	0	61
2013 (partial)	61	0	61
2014 (partial)	61	0	61
2015 (partial)	60	0	60
2016 (partial)	61	0	61
2017 (partial)	61	0	61
2018 (partial)	63	0	63
2019 (partial)	62	0	62
2020 (partial)	48	0	48
2021 (partial)	61	0	61
2022 (partial)	61	0	61
2023 (partial)	60	1	61
2024 (partial)	63	0	63
2025 (partial)	61	0	61

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 ozone	Of which fine particles	Pre-2013 rules	Days monitored
2000	0	0	0	0	150
2001	0	0	0	0	349
2002	0	0	0	0	365
2003	0	0	0	0	363
2004	0	0	0	0	366
2005	0	0	0	0	361
2006	0	0	0	0	362
2007	0	0	0	0	365
2008	0	0	0	0	359
2009	0	0	0	0	365
2010	0	0	0	0	365
2011	0	0	0	0	365
2012	0	0	0	0	366
2013	0	0	0	0	354
2014	0	0	0	0	365
2015	0	0	0	0	365
2016	0	0	0	0	366
2017	0	0	0	0	365
2018	0	0	0	0	330
2019	0	0	0	0	357
2020	0	0	0	0	365
2021	0	0	0	0	364
2022	0	0	0	0	61
2023	0	0	0	0	61
2024	0	0	0	0	63
2025	0	0	0	0	61

Sources

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