Discover the 10 States with the Best Air Quality

Written by Gerald Dlubala
Published: September 12, 2023
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The US Environmental Protection Agency (EPA) uses a numbered scale called the Air Quality Index (AQI) to report air quality conditions across the US. The AQI assigns scores to states ranging from 0-500 for easy reference and quick readability. An AQI score of 50 or below is considered good air quality, with scores over 300 deemed hazardous to our health. Calculations are based on five major pollutants, including ground-level ozone, particle pollution, carbon monoxide, sulfur dioxide, and nitrogen dioxide. The EPA issues year-round AQI forecasts, as well as daily, up-to-the-minute information for your location. All US states are generally in or very near the good air quality category. But these 10 states rank as the best when it comes to the quality of air their residents can expect to experience on a daily basis.

1. Hawaii

Ewa Beach Hawaii

Hawaii leads all US states in air quality with an AQI of 21.2.

©Asia visions photography/

With its wide open spaces and never-ending beaches, it’s no wonder that Hawaii leads the US with the best air quality. As the surrounding ocean waters work as nature’s thermostat, Hawaii’s climate variation is minimal. However, notable features of Hawaii’s weather patterns are mild year-round temperatures featuring moderate humidity, a northeasterly wind, and varying degrees of rainfall. Hawaii offers endless outdoor activities, noteworthy sunsets, and relaxing, romantic settings, and can now claim the best air quality in which to experience all that the state has to offer.

2. Alaska

Springtime in Alaska

Alaska can thank its unique geography and climate for its air quality ranking of 29.1.

©Real Window Creative/

With more coastline than all other US states combined, the State of Alaska harbors over 3 million lakes and more than 3,000 rivers within its boundaries. Bordered only by Canada, our 49th state has a unique geography and climate including harsh winters, mild summers, and a short growing season. This diverse combination may be what ultimately helps keep Alaska’s air quality near the top of the list.

3. Washington

Welcome to Washington - state sign

Washington State provides a breath of fresh air with an air quality index of 33.5.


When speaking of good air quality, Washington State traditionally ranks as a state at the top of the list. There are however, fluctuating times of poor air quality caused by sporadic wildfires or excessive wood burning in the winter due to its use as a primary fuel source. The Evergreen State finds itself with a variety of climate conditions throughout the state as you travel from west to east, and comes in as a top state in the air quality index.

4. Oregon

Gallon House covered bridge near Silverton, Oregon

Oregon’s natural beauty and welcoming landscape add to an air quality index of 36.1.

©Bob Pool/

Oregon also features varied climate conditions, ranging from coastal conditions to dryer, more extreme climates as you move easterly. Oregon’s topography, ranging from high elevation to coastal conditions influences its climate and weather patterns. Additionally, Oregon protects its environment by requiring environmental enhancements like the use of special permits and required annual emissions reports. Oregon also enforces emissions performance standards on equipment manufacturers, including the wood stove industry.

5. Maine

The Pine Tree State offers top-ten air quality with an AQI of 36.5.


Maine implements air quality programs under the Clean Air Act in conjunction with local state laws. Air quality is routinely monitored and reported, but Maine also requires licensing for emissions generated from larger facilities. Additionally, they conduct regularly scheduled inspections and compliance visits. Maine features a climate that in general, features milder summers, cooler evenings, and cold winters. Their climate combined with their diligence in testing and monitoring allows Maine residents and visitors to enjoy good air quality.

6. North Dakota

Bismarck - North Dakota, Winter, Color Image, Federal Building, Government

North Dakota and its great plains rank high with an AQI of 37.0.


The state of North Dakota features a more typical four-season climate, featuring a very comfortable and enjoyable summer, spring, and fall. Their winters can be snowy and icy, which is just fine for the residents to enjoy their winter activities. Residents can expect about 200 sunny or mostly sunny days, perfect for being outdoors with good air quality. Primary air quality concerns in the Peace Garden State come from particle pollution, including aerosol use, auto emissions, construction activities, factory emissions, and wildfire or woodburning smoke.

6. Nebraska

Oregon National Historic Trail - Scotts Bluff

The heart of the midwest, Nebraska, shares the sixth spot with an AQI of 37.0.


Residents of the Cornhusker State know that Nebraska is home to a varied climate and seasonal allergy issues. Hot and humid summers give way to cold and dry winters. But with Nebraska’s diligent efforts including permit issuance, compliance inspections, sample monitoring, and outreach support, they maintain a top air quality index. Nebraska also uses a public complaint investigation process for issues that need attention.

8. Iowa


Known for its corn and rolling landscapes, Iowa also provides clean air with an AQI of 37.6.

©Natalia Kuzmina/

Iowa appeals to all its residents to help protect the environment, including the waterways, plant life, wildlife, and air quality. The responsibility for clean air is supported on both a local and regional level as the Department of Natural Resources partners with communities, businesses, industry, organizations, and even private citizens to provide the tools and knowledge necessary to find and apply workable solutions for clean air. That effort is paying off, giving Iowa a spot in the top US states with the best air quality.

9. Minnesota

View of Minneapolis, Minnesota, Skyline

Minnesota, the Northstar State, has an air quality index of 38.3.

©Joseph Sohm/

Located in the upper Midwest, Minnesota features four seasons with some of the widest variety of weather among its beautiful landscapes. Hot summers, cold winters, and everything in between can play havoc with the environment. Minnesota’s air quality is kept up to standard with the help of grassroots programs featuring neighborhood sources, pollution reduction grants and loans, and following federal standards and reducing greenhouse gases.

10. Vermont

Mad River in Warren, Vermont

Vermont rounds out the top 10 best air quality states with an AQI of 38.5.

©Wirestock Creators/

With its natural beauty and mesmerizing landscape, Vermont is often mentioned as a picturesque, beautiful place for a getaway. But in addition to the aesthetics, Vermont has enacted its own climate quality projects with benchmarks to reduce greenhouse gases and pollution, enabling it to continue to rank high in air quality.

RankStateAQI Score
3Washington State33.5
6North Dakota37.0

The photo featured at the top of this post is © Public Domain, via Wikimedia Commons – Gfp-ohio-alum-creek-state-park-beach-and-sky" rel="nofollow noopener noreferrer" target="new" class="text-muted">License / Original

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About the Author

Gerald Dlubala is a writer at A-Z Animals where his primary focus is on animals, plants, and places. Gerald has been writing for over 25 years and holds a Bachelor's Degree from the University of Missouri-St. Louis. Gerald has shared his home with numerous pets, including dogs, cats, a variety of fish and newts, turtles, hermit crabs, rabbits, and a flock of birds. Gerald enjoys all animal and plant life and looks at every day as an opportunity to learn something new about the world around us.

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