Air Quality Rankings 2026 — Worst & Best ZIP Codes

Rank	State	Avg Score
1	OK	AQI 72.1
2	TX	AQI 61.5
3	AZ	AQI 61.3
4	GA	AQI 56.3
5	PA	AQI 55.3
6	AK	AQI 54.2
7	NJ	AQI 53.8
8	CO	AQI 53.3
9	DE	AQI 52.7
10	VA	AQI 52.4
11	KS	AQI 52
12	OH	AQI 51.3
13	MD	AQI 50.8
14	AR	AQI 50.7
15	RI	AQI 50.4

ZIP codes 93512 and 93517 — Benton and Bridgeport, California — sit at the top of this ranking with an Air Quality Index of 1,006, a score the EPA classifies as Hazardous and reserves for conditions dangerous to the entire population. Both are small communities in Mono County, tucked into the Eastern Sierra at elevations above 6,000 feet. Thirteen more ZIP codes cluster in the Flathead Valley around Kalispell, Montana — Bigfork, Columbia Falls, Hungry Horse, Kila, Lake Mc Donald, Lakeside, Martin City, Olney, Somers, Whitefish, and three Kalispell ZIPs — each recording an AQI of 121, driven by PM10. Ten more land in the Fort Collins, Colorado corridor from Bellvue to Berthoud with an AQI of 111, dominated by PM2.5. Three regions, three pollution mechanisms — and none of them are what most people think of when they picture bad air.

Welcome to the 2026 Air Quality Rankings. We analyzed 28,661 ZIP codes using EPA AirNow monitoring station data, which feeds the national Air Quality Index — a composite score that translates raw pollutant concentrations into a single 0–500 scale (values above 500 are measured but designated "Beyond AQI"). Each ZIP code in this dataset is matched to the nearest active AirNow monitoring station; the AQI value reflects the most recently available reading at the time of data collection. The ranking is sorted descending: the worst air quality appears at the top.

What the data reveals. The geography of America's highest-AQI ZIP codes is not random, and it is not a simple story about industrial cities or traffic corridors. The Eastern Sierra entries in Mono County record extreme PM10 spikes tied to dust events from dry lakebeds — most notably the exposed playa of Owens Lake, which after decades of water diversion became one of the largest sources of windblown particulate dust in the western United States. The Flathead Valley cluster around Kalispell tells a different story: a mountain basin surrounded by ranges that trap cold air during inversions, concentrating particulate matter from wood-burning stoves, agriculture, and wildfire smoke carried in from the northern Rockies. Fort Collins sits in the Northern Front Range airshed, where PM2.5 from vehicle emissions, oil and gas operations to the east, and periodic wildfire smoke from Colorado and Wyoming combine — and where topography channels pollution before it disperses.

The top of the list. The cleanest air in this dataset is found in Wyoming's Big Horn Basin: five ZIP codes covering Cody, Meeteetse, Powell, Ralston, and Wapiti all record an AQI of exactly 0. That is not an error — it reflects near-zero pollutant concentrations at monitoring stations in a region with low vehicle density, minimal industrial activity, and favorable wind patterns that prevent accumulation. Eight ZIP codes in Alaska's Matanuska-Susitna Borough — Wasilla, Palmer, Sutton, Chugiak, and Houston — follow at AQI 2, consistent with the clean-air baseline of a sparsely populated subarctic valley. Rounding out the best 25 are twelve ZIP codes in the South Lake Tahoe, California area, each at AQI 3 — elevation, national forest buffers, and favorable winds produce a clean-air pocket even within California's heavily monitored airshed. California leads all states with 2,518 ranked ZIP codes, followed by Pennsylvania (1,515) and Florida (1,465).

How to read this ranking. An AQI value in this dataset is a point-in-time measurement, not a long-run average. A ZIP code that records 1,006 during a dust event or wildfire episode will appear at the top of this list even if conditions are moderate 300 days a year. Conversely, a ZIP that posts AQI 0 may face seasonal spikes that fell outside the measurement window. This ranking is most useful for relative comparison within a region — it tells you which communities face documented air quality stress, and it tells you what pollutant is driving that stress (PM10 vs. PM2.5 vs. ozone). Use the tables below as a starting point, then consult the EPA AirNow monitoring history for any specific ZIP to understand seasonal variation before drawing conclusions.

What this ranking does not tell you. It does not measure indoor air quality, which is where most Americans spend the majority of their time and where pollutant concentrations often exceed outdoor levels. It does not capture radon — a carcinogenic gas with no odor that accumulates in basements regardless of outdoor AQI. It does not account for chronic low-level ozone exposure in urban areas that may not push past the monitoring threshold on any single day but accumulates health risk over years. And because AirNow coverage is denser in cities and near population centers, rural ZIP codes in this dataset are often matched to more distant stations, which may underrepresent or overrepresent true local conditions. A reading from a station 15 miles away carries different weight than one from a station at the ZIP code boundary.

28,661 ZIP codes analyzed · Data last refreshed 2026-04-12

28,665 ZIP codes analyzed · Worst score: 188

28,893 ZIP codes analyzed · Worst score: 174

28,786 ZIP codes analyzed · Worst score: 331

25 Worst ZIP Codes

#	ZIP Code	City	State	AQI	Category	Pollutant
1	43402	Bowling Green	OH	331	Hazardous	PM2.5
2	43403	Bowling Green	OH	331	Hazardous	PM2.5
3	43406	Bradner	OH	331	Hazardous	PM2.5
4	43408	Clay Center	OH	331	Hazardous	PM2.5
5	43412	Curtice	OH	331	Hazardous	PM2.5
6	43413	Cygnet	OH	331	Hazardous	PM2.5
7	43414	Dunbridge	OH	331	Hazardous	PM2.5
8	43416	Elmore	OH	331	Hazardous	PM2.5
9	43430	Genoa	OH	331	Hazardous	PM2.5
10	43431	Gibsonburg	OH	331	Hazardous	PM2.5
11	43432	Graytown	OH	331	Hazardous	PM2.5
12	43434	Harbor View	OH	331	Hazardous	PM2.5
13	43435	Helena	OH	331	Hazardous	PM2.5
14	43437	Jerry City	OH	331	Hazardous	PM2.5
15	43439	Lacarne	OH	331	Hazardous	PM2.5
16	43441	Lemoyne	OH	331	Hazardous	PM2.5
17	43442	Lindsey	OH	331	Hazardous	PM2.5
18	43443	Luckey	OH	331	Hazardous	PM2.5
19	43445	Martin	OH	331	Hazardous	PM2.5
20	43447	Millbury	OH	331	Hazardous	PM2.5
21	43449	Oak Harbor	OH	331	Hazardous	PM2.5
22	43450	Pemberville	OH	331	Hazardous	PM2.5
23	43451	Portage	OH	331	Hazardous	PM2.5
24	43457	Risingsun	OH	331	Hazardous	PM2.5
25	43458	Rocky Ridge	OH	331	Hazardous	PM2.5

25 Best ZIP Codes

#	ZIP Code	City	State	AQI	Category	Pollutant
1	99695	Anchorage	AK	6	Good	PM10
2	99694	Houston	AK	6	Good	PM10
3	99652	Big Lake	AK	6	Good	PM10
4	99623	Wasilla	AK	6	Good	PM10
5	99605	Hope	AK	6	Good	PM10
6	99599	Anchorage	AK	6	Good	PM10
7	99587	Girdwood	AK	6	Good	PM10
8	99577	Eagle River	AK	6	Good	PM10
9	99567	Chugiak	AK	6	Good	PM10
10	99540	Indian	AK	6	Good	PM10
11	99530	Anchorage	AK	6	Good	PM10
12	99529	Anchorage	AK	6	Good	PM10
13	99524	Anchorage	AK	6	Good	PM10
14	99523	Anchorage	AK	6	Good	PM10
15	99522	Anchorage	AK	6	Good	PM10
16	99521	Anchorage	AK	6	Good	PM10
17	99520	Anchorage	AK	6	Good	PM10
18	99519	Anchorage	AK	6	Good	PM10
19	99518	Anchorage	AK	6	Good	PM10
20	99517	Anchorage	AK	6	Good	PM10
21	99516	Anchorage	AK	6	Good	PM10
22	99515	Anchorage	AK	6	Good	PM10
23	99514	Anchorage	AK	6	Good	PM10
24	99513	Anchorage	AK	6	Good	PM10
25	99511	Anchorage	AK	6	Good	PM10

Rankings by State

State	ZIP Codes
California	2,526
Pennsylvania	1,510
Florida	1,436
Texas	1,356
North Carolina	1,234
Illinois	999
New York	969
Ohio	863
Indiana	845
Michigan	834
New Jersey	789
Virginia	787
Kentucky	706
West Virginia	681
Massachusetts	667
Tennessee	667
Missouri	659
Washington	646
Wisconsin	623
Maryland	615
Georgia	594
Connecticut	584
Minnesota	543
Iowa	540
Louisiana	491

Methodology

Air quality rankings use EPA AirNow Air Quality Index (AQI) data from monitoring stations across the country. AQI values above 100 are unhealthy for sensitive groups; above 150 is unhealthy for everyone. Rankings reflect the most recent available monitoring data. Data source: EPA AirNow API.

Last updated: 2026-07-19.

Frequently Asked Questions

How are these rankings calculated?

Rankings are based on federal agency data including EPA, FEMA, USGS, and PHMSA. Each ZIP code receives a score based on the specific risk factors for this category. See the methodology section above for details.

How often are rankings updated?

Rankings are regenerated quarterly using the latest available data. The date shown reflects the most recent update.

Air Quality Rankings 2026 — Worst & Best ZIP Codes

Average Air Quality Index by State

Top 15 States

AQI Category Distribution

States with Worst Air Quality

25 Worst ZIP Codes

25 Best ZIP Codes

Rankings by State

Methodology

Frequently Asked Questions

How are these rankings calculated?

How often are rankings updated?

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