Bad Air Days in Stark County, Ohio: 3 a Year

3 bad air days a year

About the middle of monitored US counties. Ranked 351 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (34% particle days).

Which months to watch

Most bad days here fall in June and July and May. Averaged over 2016 to 2025.

Is a purifier worth it here?

Bad air days are rare here. A standard furnace filter is enough; no purifier needed for outdoor air.
On the odd bad day, check AirNow and keep windows shut.

The record for Stark

In 2000 to 2009 this county averaged 27 bad days a year; in 2016 to 2025, 3. The air has improved. The worst recent year was 2023, with 10 bad days on 365 monitored days.

Date	AQI	Main pollutant
2023-06-28	283	PM2.5
2023-06-29	214	PM2.5
2023-07-17	155	PM2.5
2022-06-21	136	Ozone
2021-07-20	127	PM2.5

Most days, not the worst ones

Across 3,645 monitored days from 2016 to 2025, the air in Stark County rated Good on 50% of them, less often than the 72% typical of monitored counties, and Moderate on 49%. The median day sat at AQI 50; one day in ten went above 70.

The pollutant setting the AQI on an ordinary day here:

fine particles (PM2.5)68%2,492 days
ozone31%1,146 days

Year by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	365	194	169	2	0	49	124
2024	366	192	174	0	0	48	93
2023	365	163	192	10	3	52	283
2022	365	206	157	2	0	49	136
2021	365	154	208	3	0	53	127
2020	358	202	152	4	0	47	119
2019	365	157	208	0	0	52	100
2018	365	176	186	3	0	51	108
2017	365	179	184	2	0	51	119
2016	366	216	144	6	0	45	119
2015	365	207	151	7	0	46	108
2014	365	195	168	2	0	49	108
2013	365	130	232	3	0	53	112
2012	366	108	237	21	1	57	192
2011	365	109	244	12	2	57	154
2010	365	98	242	25	1	60	156

*2025 may be a partial year in EPA's file.

Elsewhere in Ohio

How this is counted

A bad air day is a day the county's daily AQI from EPA AirData went above 100, the level where EPA tells children, older adults and people with asthma or heart disease to cut back outdoors. Monitors do not run every day, so yearly counts are scaled to 365 days. This is the record, not today's air: for that, check AirNow. More on the method in how the county numbers are made, on the AQI 100 line in what counts as a bad air day, and on why a purifier does not touch ozone in smoke vs ozone.