Bad Air Days in Portage County, Ohio: 2 a Year

2 bad air days a year

Fewer bad air days than most monitored US counties. Ranked 534 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (0% particle days).

When the bad days come in Portage

Most bad days here fall in June and July. 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.

Better or worse than it was

In 2000 to 2009 this county averaged 25 bad days a year; in 2016 to 2025, 2. The air has improved. The worst recent year was 2022, with 4 bad days on 282 monitored days.

Date	AQI	Main pollutant
2022-06-22	159	Ozone
2023-06-29	159	Ozone
2025-07-15	150	Ozone
2022-06-21	140	Ozone
2025-06-12	119	Ozone

Most days, not the worst ones

Across 2,615 monitored days from 2016 to 2025, the air in Portage County rated Good on 80% of them, more often than the 72% typical of monitored counties, and Moderate on 19%. The median day sat at AQI 40; one day in ten went above 61.

The pollutant setting the AQI on an ordinary day here:

ozone85%2,217 days
fine particles (PM2.5)15%398 days

Portage County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	245	190	53	2	0	43	150
2024	245	187	56	2	0	43	108
2023	241	178	60	3	1	43	159
2022	282	226	52	4	1	41	159
2021	263	205	57	1	0	40	108
2020	262	226	35	1	0	40	101
2019	270	233	37	0	0	38	87
2018	279	214	65	0	0	39	100
2017	281	226	55	0	0	40	97
2016	247	209	38	0	0	38	90
2015	260	211	49	0	0	38	93
2014	242	192	50	0	0	37	87
2013	237	198	39	0	0	32	90
2012	259	158	94	7	1	44	164
2011	259	174	82	3	0	40	122
2010	260	176	80	4	0	43	126

*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.