Harrison County, West Virginia air quality history

Daily Air Quality Index summaries from EPA monitors in Harrison, West Virginia, 1999–2025.

72%

Good days in 2017

Median daily AQI, 2017

Days above 100 in 2017

122

Days with an AQI in 2017 (of 365)

In 2017, EPA reported a daily Air Quality Index (AQI) for Harrison, West Virginia on 122 days. 88 of those days (72%) were in the Good range, and the median daily AQI was 40. That median is about the same as the typical monitored county in West Virginia (median 40 across 13 counties), and about the same as the typical monitored U.S. county (41). The main pollutant was fine particles (PM2.5) on 122 days.

EPA did not report an AQI for every day of 2017 here (122 of 365 days). Figures describe monitored days only; seasonal monitoring (for example, ozone measured only in warmer months) can make a county look cleaner or dirtier than a full-year record would.

Years with fewer than 120 monitored days (2020, 2021, 2022, 2023, 2024, 2025…) are shown in the table but left out of comparisons and trend statements.

How the days broke down each year

Each bar is one year. The colored segments show the share of monitored days that fell in each AQI category.

Good
Moderate
Unhealthy for Sensitive Groups
Unhealthy
Very Unhealthy
Hazardous

Typical and high-end AQI over time

The median is the middle day of the year. The 90th percentile is the level that only the highest 10% of days exceeded.

Median daily AQI
90th-percentile daily AQI

Main pollutant by day, 2017

On each monitored day, the AQI reflects whichever measured pollutant had the highest index. This counts how many days each pollutant set the AQI. A pollutant that was not measured here cannot appear.

Pollutant	Days as main pollutant	Share of monitored days
Fine particles (PM2.5)	122	100%

Year-by-year data

Annual AQI summary by year
Year	Days with AQI	Good	Moderate	Unhealthy for Sensitive Groups	Unhealthy	Median AQI	90th pct.	Max AQI	Main pollutant
2025	116	84	32	0	0	33	55	68	PM2.5
2024	113	91	22	0	0	34	54	60	PM2.5
2023	107	82	24	0	1	39	61	166	PM2.5
2022	113	93	20	0	0	34	55	69	PM2.5
2021	115	82	33	0	0	35	58	69	PM2.5
2020	118	99	19	0	0	35	53	80	PM2.5
2019	111	84	27	0	0	41	56	64	PM2.5
2018	117	88	29	0	0	36	58	65	PM2.5
2017	122	88	34	0	0	40	56	71	PM2.5
2016	117	78	39	0	0	41	56	66	PM2.5
2015	116	65	51	0	0	46	61	86	PM2.5
2014	120	68	52	0	0	44	59	76	PM2.5
2013	119	71	48	0	0	46	61	73	PM2.5
2012	115	56	59	0	0	51	61	86	PM2.5
2011	83	41	42	0	0	51	64	80	PM2.5
2010	111	39	71	1	0	56	67	117	PM2.5
2009	118	47	71	0	0	53	65	75	PM2.5
2008	119	36	83	0	0	56	71	87	PM2.5
2007	121	35	85	1	0	57	80	108	PM2.5
2006	118	38	78	2	0	58	78	102	PM2.5
2005	119	28	90	1	0	59	83	113	PM2.5
2004	119	33	84	2	0	56	73	109	PM2.5
2003	118	30	87	1	0	56	74	116	PM2.5
2002	115	39	73	2	1	56	76	155	PM2.5
2001	120	29	88	3	0	57	80	120	PM2.5
2000	115	31	83	1	0	60	79	103	PM2.5
1999	116	30	84	2	0	59	79	134	PM2.5

What this data can and can’t tell you

It is a county-level summary. EPA reports one AQI per day for the county, based on the monitors operating there. Air at a particular street, school or home can differ, especially near roads, industry or wildfire smoke.

It is not a health assessment. The AQI is EPA’s scale for communicating daily air quality. A county’s history can’t tell you what the health risk is for any particular person. For daily conditions and health guidance, see AirNow.

Rules change over time. EPA has revised AQI breakpoints, most recently for fine particles in 2024, so some year-to-year change can reflect the scale rather than the air.

All monitored counties in West Virginia

Source: U.S. EPA AirData, “Annual AQI by County” files for 1999–2025 (EPA download page). EPA file dates: 2026-06-26. Imported into EnviroNearby November 5, 2026. How we use this data · Report a problem