National ranking · cleanest air

Best Air Quality in the US (2025)

Ranked by the highest share of Good air days among counties with at least 100 monitored days in 2025, the counties where residents breathe the cleanest air most often, from EPA Air Quality System monitoring.

Compiled by PlainAirData · August 23, 2026

97.8%
#1 Prince Edward, Virginia: 28
Counties ranked

Prince Edward County, Virginia leads the 2025 cleanest-air list among 28 ranked U.S. counties (97.8% Good)

According to the U.S. EPA Air Quality System, this ranking orders 28 counties with at least 100 monitored days in 2025 by the highest share of days in the Good AQI band, using median AQI to separate near-ties. It describes a historical reporting year, not today's air quality. For current conditions and alerts, use AirNow.

Data source EPA Air Quality System (AQS)

#1 Good-day share: Prince Edward County, Virginia ranks #1 of 28 for Good-day share at 97.8%.
#1 median AQI: #1 median AQI: 33
Counties ranked: Counties ranked: 28
Tied at 100% Good: Tied at 100% Good: 0

Data updated August 2026 from the compiled EPA AQS release in this database.

Counties below the 100-day monitoring floor are excluded: with only a handful of readings, a single clean stretch can push a county to a 100% Good-day rate that a normal year's weather would not hold up. 0 counties tie at 100.0% with this floor applied, all with a genuinely large sample of monitored days. For comparison, the cohort median across all 951 floor-qualifying counties is 77.5%, meaning the difference between a top-ranked county and a typical monitored county is real, not sampling noise.

Filter this ranking

Filters keep the Good-day-share ranking contract. A state filter ranks that state's qualifying counties; pollutant filters keep rows whose annual day-type count is led by ozone, PM2.5, or PM10. Raising the monitored-days floor tightens the sample beyond the default 100-day Module-34 guard.

Showing 28 matching Virginia counties . Back to the national top 50.

Where the national cleanest cohort concentrates

Among the unfiltered national top 50 (highest Good-day share, ≥100 monitored days), Virginia contributes 6 counties , followed by Wyoming (4). State filters rank every qualifying county inside one jurisdiction.

Compare any two counties

For a side-by-side annual change view, open the county compare tool.

Cleanest of the clean: lowest median AQI

Among the top counties (all near a 100% Good-day record), the lowest typical AQI. Shorter is cleaner.

Median AQI · EPA Air Quality System

Ranked counties

#	County	State	Good Days %	Median AQI	Good Days	Days Monitored	Day driver
1	Prince Edward	Virginia	97.8%	33 Good	318	325	Ozone
2	Fauquier	Virginia	97.5%	34 Good	239	245	Ozone
3	Suffolk City	Virginia	96.7%	38 Good	237	245	Ozone
4	Caroline	Virginia	96.7%	35 Good	235	243	Ozone
5	Hanover	Virginia	96.7%	36 Good	233	241	Ozone
6	Stafford	Virginia	96.4%	35 Good	347	360	Ozone
7	Prince William	Virginia	95.6%	35 Good	349	365	Ozone
8	Giles	Virginia	94.4%	37 Good	337	357	Ozone
9	Wythe	Virginia	94.1%	39 Good	225	239	Ozone
10	Rockbridge	Virginia	93.9%	36 Good	248	264	Ozone
11	Charles	Virginia	88.7%	35 Good	323	364	PM2.5
12	Arlington	Virginia	87.4%	37 Good	319	365	Ozone
13	Norfolk City	Virginia	86.0%	33 Good	312	363	PM2.5
14	Madison	Virginia	85.8%	40 Good	283	330	Ozone
15	Lynchburg City	Virginia	85.2%	30 Good	92	108	PM2.5
16	Roanoke	Virginia	83.8%	37 Good	306	365	PM2.5
17	Hampton City	Virginia	83.0%	38 Good	303	365	PM2.5
18	Albemarle	Virginia	81.0%	38 Good	294	363	PM2.5
19	Virginia Beach City	Virginia	80.8%	34 Good	295	365	PM2.5
20	Chesterfield	Virginia	80.8%	39 Good	294	364	PM2.5
21	Loudoun	Virginia	80.5%	40 Good	294	365	Ozone
22	Rockingham	Virginia	80.0%	39 Good	292	365	PM2.5
23	Salem City	Virginia	79.7%	31 Good	90	113	PM2.5
24	Richmond City	Virginia	78.9%	36 Good	288	365	PM2.5
25	Bristol City	Virginia	78.0%	34 Good	85	109	PM2.5
26	Fairfax	Virginia	77.8%	42 Good	284	365	Ozone
27	Henrico	Virginia	75.8%	40 Good	276	364	Ozone
28	Frederick	Virginia	74.0%	39 Good	270	365	PM2.5

Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS). Good Days % is the share of monitored days with AQI at or below 50. Counties ranked by good_pct descending

Every figure on PlainAirData is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.