The Top 7 U.S. Capital Cities with the Cleanest Air Quality

As the government seats of their respective states, capital cities are often congested with traffic, commerce, and manufacturing, leading to high levels of air pollution. However, some capital cities in the United States have air that is largely free from particulates and ozone pollution despite their size and development. Keep reading to learn about the top seven U.S. capital cities with the best air quality.

The rankings in this list are based on data from the U.S. Environmental Protection Agency as well as the American Lung Association. The cities below all have good Air Quality Index (AQI) scores, in addition to being ranked among the cleanest U.S. cities by the American Lung Association. The AQI is based on levels of five major air contaminants. A good score ranges from 0-50, which indicates there is little to no risk from air pollution.

7. Raleigh, North Carolina

Located in North Carolina’s Piedmont region, Raleigh is ranked by the American Lung Association as one of the cleanest cities for ozone pollution. The city has an AQI of 40, which is within the EPA’s standard for “good” air quality. 

Raleigh was established in 1729. The city’s founders referred to Raleigh as the “City of Oaks” and set an early precedent of prioritizing the city’s parks and green spaces. Today, Raleigh has more than 9,000 acres of parks and over 180 miles of greenway trails, including the state’s longest biking trail. The Neuse River Greenway trail spans 27 miles through Raleigh, offering bikers and walkers excellent views of the river.

In addition to parks and trails, Raleigh boasts several lakes in the surrounding area. Lake Crabtree is popular for sailing, while Falls Lake is more popular for swimming and fishing. While Raleigh is one of the U.S. capital cities with the best air quality, smoke from wildfires in western North Carolina caused several days of elevated air pollution in 2023. 

6. Lansing, Michigan

Situated along the banks of the Grand and Red Cedar Rivers, Lansing tops the American Lung Association lists for cleanest cities for ozone pollution and 24-hour particles. According to the EPA, Lansing’s AQI is 19, making it one of the U.S. capital cities with the cleanest air.

Dense forests covered the Lansing area before it was a city. Settlers began to arrive in the region in the early 1800s, and development in the city increased after it was named the state capital in 1847. Lansing experienced steady growth over the following decades, thanks in part to the railroad and, later, automobile manufacturing. 

Today, Lansing boasts three nature centers that each have hiking trails and outdoor activities for all ages. Many of Lansing’s trails connect with parks, recreation centers, and other trails to create a network for walking, biking, and enjoying the fresh air. However, Lansing did experience several days with unhealthy air quality in 2023 due to smoke from wildfires in Canada.

5. Des Moines, Iowa

The capital city of Iowa boasts an AQI of 41 from the EPA. In addition, it is tied for first place for the ALA’s cleanest metro areas for ozone pollution, and the city also has low rates of particulate pollution.

Although it is growing quickly, Des Moines maintains over 4,000 acres of parks within the city and over 80 miles of trails. Residents in Des Moines have an average commute time of around 20 minutes, which also helps to keep air pollution levels low. However, Iowa’s air quality suffered in 2023 due to increased ozone pollution and wildfire smoke.

Residents in Des Moines can enjoy the fresh air by camping, fishing, or kayaking at nearby Saylorville Lake. Outdoor attractions like the Greater Des Moines Botanical Garden and the Des Moines Water Works Park are also popular with local residents.

4. Lincoln, Nebraska

Located in southeastern Nebraska, the city of Lincoln is tied for first place on two different American Lung Association rankings. Lincoln is one of the top two cleanest cities for both ozone and particle pollution. Lincoln’s AQI score of 31 reflects this distinction.

Established in 1896, Lincoln has grown steadily to a current population of nearly 300,000. Although Lincoln has a robust economy based on manufacturing, education, and healthcare, it has maintained its greenspaces. Over 80% of homes in Lincoln are located within a half-mile of a park, and almost 100% of the city’s homes are no more than one mile from a public hiking trail. Residents can also explore areas like Pawnee Lake for fishing, boating, and kayaking.

While Lincoln residents typically enjoy some of the cleanest air in the country, the city was impacted in 2023 by smoke from Canadian wildfires. The smoke caused reduced visibility within the city and created unhealthy conditions for days.

3. Bismark, North Dakota

With an AQI of 25, Bismarck is easily among U.S. capital cities with the best air quality. In addition to the EPA’s measurement, the city ranks 21st on the American Lung Association’s list of cleanest U.S. cities by particle pollution.

Despite North Dakota’s large size, it is the state with the third-smallest population in the country. North Dakota has a long tradition of agriculture and ranching and is the country’s leading producer of honey and sunflowers. The state has over 33,000 farms, and over 90% of North Dakota’s land is used for agriculture.

Bismarck is home to just over 700,000 residents, and the Missouri River creates the city’s western border. The local government maintains around 50 parks, including historic areas and athletic fields. In addition, Bismarck contains over 30 miles of hiking trails, including access to the Missouri Valley Trail. 

2. Cheyenne, Wyoming

Located in the southeastern corner of Wyoming, Cheyenne has an AQI of 10 and is ranked the third cleanest city by the American Lung Association for annual particle pollution. 

The state of Wyoming has been a national leader in conservation. In 1891, President Benjamin Harrison established the Shoshone National Forest as the country’s first national forest. North of Cheyenne, Devil’s Tower was named the country’s first national monument. Closer to the city, residents can explore the outdoors at Curt Gowdy State Park or Vedauwoo Recreation Area. 

In the mid-1800s, Cheyenne’s abrupt development earned it the nickname “The Magic City.” Today, Cheyenne is the most populated city in Wyoming, although it has a lower population than many other state capitals, with 65,000 residents. While Cheyenne has had some of the country’s best air quality for years, recent wildfires have increased the ozone pollution and particulates in the air.

1. Honolulu, Hawaii

Hawaii’s capital city is home to world-class beaches and abundant tropical beauty. In addition, it is also tied for first place for the American Lung Association’s cleanest metro area for ozone. The ALA also ranks Honolulu as the country’s cleanest metro area for particle pollution in 24 hours. The city’s AQI rating is 18, making Honolulu one of the capital cities with the best air quality.

Honolulu ranks among the nation’s most walkable cities, with many areas of the city easily navigable by foot. Residents in Honolulu can enjoy one of the city’s golf courses, explore the Honolulu Zoo, or stroll through its many parks. 

Although Honolulu is among the U.S. capital cities with the best air quality, the devastating wildfire in Maui in 2023 released many harmful particulates into the air, leading the state government to install sensors in the neighborhood of Lahaina to allow residents to keep track of daily air quality alerts.

Summary of U.S Capital Cities With the Cleanest Air Quality

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