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

1 bad air day a year

Fewer bad air days than most monitored US counties. Ranked 670 of 996 monitored counties, where 1 is worst.

What makes them bad: a mix of particles and ozone (50% particle days).

Which months to watch

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

What actually helps 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 worst days on file

In 2000 to 2009 this county averaged 18 bad days a year; in 2016 to 2025, 1. The air has improved. The worst recent year was 2023, with 5 bad days on 277 monitored days.

Date	AQI	Main pollutant
2023-06-29	171	PM2.5
2023-06-08	135	PM2.5
2019-12-23	127	PM2.5
2019-12-26	116	PM2.5
2023-06-01	115	Ozone

Most days, not the worst ones

Across 2,746 monitored days from 2016 to 2025, the air in Berkeley 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 57.

The pollutant setting the AQI on an ordinary day here:

ozone71%1,961 days
fine particles (PM2.5)29%785 days

Berkeley County by year

Year	Days monitored	Good	Moderate	Over 100	Over 150	Median AQI	Highest AQI
2025*	269	225	44	0	0	39	87
2024	275	217	58	0	0	42	97
2023	277	206	66	5	1	44	171
2022	275	230	45	0	0	38	88
2021	273	214	59	0	0	40	93
2020	278	244	34	0	0	38	95
2019	278	233	43	2	0	40	127
2018	281	229	52	0	0	39	88
2017	285	226	59	0	0	40	77
2016	255	186	68	1	0	42	112
2015	254	162	92	0	0	47	100
2014	250	178	72	0	0	44	91
2013	263	188	74	1	0	43	131
2012	254	147	106	1	0	47	140
2011	263	171	91	1	0	46	105
2010	258	128	117	13	1	51	159

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

West Virginia compared

Ohio 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.