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

28,803 ZIP codes analyzed · Worst score: 166

25 Worst ZIP Codes

#	ZIP Code	City	State	AQI	Category	Pollutant
1	92321	Cedar Glen	CA	166	Unhealthy	Ozone
2	92322	Cedarpines Park	CA	166	Unhealthy	Ozone
3	92325	Crestline	CA	166	Unhealthy	Ozone
4	92352	Lake Arrowhead	CA	166	Unhealthy	Ozone
5	92378	Rimforest	CA	166	Unhealthy	Ozone
6	92382	Running Springs	CA	166	Unhealthy	Ozone
7	92385	Skyforest	CA	166	Unhealthy	Ozone
8	92391	Twin Peaks	CA	166	Unhealthy	Ozone
9	92407	San Bernardino	CA	166	Unhealthy	Ozone
10	92414	San Bernardino	CA	166	Unhealthy	Ozone
11	92220	Banning	CA	156	Unhealthy	Ozone
12	92223	Beaumont	CA	156	Unhealthy	Ozone
13	92230	Cabazon	CA	156	Unhealthy	Ozone
14	92282	Whitewater	CA	156	Unhealthy	Ozone
15	91310	Castaic	CA	151	Unhealthy	Ozone
16	91321	Newhall	CA	151	Unhealthy	Ozone
17	91322	Newhall	CA	151	Unhealthy	Ozone
18	91342	Sylmar	CA	151	Unhealthy	Ozone
19	91350	Santa Clarita	CA	151	Unhealthy	Ozone
20	91351	Canyon Country	CA	151	Unhealthy	Ozone
21	91354	Valencia	CA	151	Unhealthy	Ozone
22	91355	Valencia	CA	151	Unhealthy	Ozone
23	91380	Santa Clarita	CA	151	Unhealthy	Ozone
24	91381	Stevenson Ranch	CA	151	Unhealthy	Ozone
25	91382	Santa Clarita	CA	151	Unhealthy	Ozone

25 Best ZIP Codes

#	ZIP Code	City	State	AQI	Category	Pollutant
1	99155	Nespelem	WA	1	Good	PM2.5
2	98855	Tonasket	WA	1	Good	PM2.5
3	98849	Riverside	WA	1	Good	PM2.5
4	98841	Omak	WA	1	Good	PM2.5
5	98840	Okanogan	WA	1	Good	PM2.5
6	98829	Malott	WA	1	Good	PM2.5
7	98819	Conconully	WA	1	Good	PM2.5
8	98812	Brewster	WA	1	Good	PM2.5
9	82450	Wapiti	WY	4	Good	PM2.5
10	82440	Ralston	WY	4	Good	PM2.5
11	82435	Powell	WY	4	Good	PM2.5
12	82433	Meeteetse	WY	4	Good	PM2.5
13	82414	Cody	WY	4	Good	PM2.5
14	59477	Simms	MT	4	Good	PM2.5
15	59467	Pendroy	MT	4	Good	PM2.5
16	59436	Fairfield	MT	4	Good	PM2.5
17	59433	Dutton	MT	4	Good	PM2.5
18	59425	Conrad	MT	4	Good	PM2.5
19	59422	Choteau	MT	4	Good	PM2.5
20	59419	Bynum	MT	4	Good	PM2.5
21	59416	Brady	MT	4	Good	PM2.5
22	59410	Augusta	MT	4	Good	PM2.5
23	96785	Volcano	HI	6	Good	PM2.5
24	96778	Pahoa	HI	6	Good	PM2.5
25	96771	Mountain View	HI	6	Good	PM2.5

Rankings by State

State	ZIP Codes
California	2,521
Pennsylvania	1,510
Florida	1,465
Texas	1,356
North Carolina	1,234
Illinois	1,028
New York	969
Ohio	865
Indiana	796
New Jersey	789
Virginia	787
Michigan	776
Kentucky	709
West Virginia	681
Massachusetts	667
Tennessee	667
Washington	667
Missouri	659
Minnesota	630
Wisconsin	627
Maryland	615
Georgia	594
Connecticut	584
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: 2026-06-04.

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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