Bad Air Days in Ohio County, West Virginia: 1 a Year

1 bad air day a year

Fewer bad air days than most monitored US counties. Ranked 647 of 996 monitored counties, where 1 is worst.

What makes them bad: mostly ozone: summer smog (22% particle days).

When the bad days come in Ohio

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.

The record for Ohio

In 2000 to 2009 this county averaged 21 bad days a year; in 2016 to 2025, 1. The air has improved. The worst recent year was 2023, with 4 bad days on 280 monitored days.

Date	AQI	Main pollutant
2023-06-29	184	PM2.5
2016-06-11	108	Ozone
2016-05-25	105	Ozone
2018-06-30	105	Ozone
2023-06-01	105	Ozone

Most days, not the worst ones

Across 2,782 monitored days from 2016 to 2025, the air in Ohio County rated Good on 80% of them, more often than the 72% typical of monitored counties, and Moderate on 20%. The median day sat at AQI 41; one day in ten went above 57.

The pollutant setting the AQI on an ordinary day here:

ozone72%1,999 days
fine particles (PM2.5)28%783 days

Ohio County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	278	225	53	0	0	40	97
2024	272	219	53	0	0	41	84
2023	280	224	52	4	1	41	184
2022	283	247	36	0	0	37	70
2021	285	223	62	0	0	39	78
2020	274	232	41	1	0	40	101
2019	283	226	57	0	0	42	71
2018	283	225	57	1	0	41	105
2017	283	218	65	0	0	43	87
2016	261	176	82	3	0	44	108
2015	251	165	84	2	0	44	112
2014	258	176	81	1	0	44	120
2013	264	188	74	2	0	43	112
2012	265	142	112	11	1	49	154
2011	264	148	109	7	0	48	126
2010	258	115	136	7	0	53	140

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

West Virginia compared

Berkeley County1/yr
Hancock Countyunder 1/yr
Wood Countyunder 1/yr
Marshall Countyunder 1/yr
Kanawha Countyunder 1/yr
Cabell Countyunder 1/yr
Brooke Countyunder 1/yr
Marion Countythin data

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.