Salt Lake City, Utah
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Up in the Air: Smog Hot Spots

After more than 50 years, the Clean Air Act still helps clean up air pollution in much of the nation. But about four in 10 Americans still live in areas with unhealthy air. This can make it hard to breathe. It also makes many health issues, such as asthma, lung cancer, heart attacks, and strokes, more likely. Is your city one of the smoggy ones? See the American Lung Association's current top 10 smog cities list to find out.

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new york city
2 / 19

No. 10: New York City; Newark, NJ; Connecticut; Pennsylvania

This sprawling metro area moves one spot on the list, from ninth in 2017, but is still among the top 10 smoggiest, thanks in part to the vast number of cars. Worse, New York City fails EPA standards for both dangerous particle pollution and ozone. In all, more than 23 million people breathe this gunky air.

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3 / 19

No. 9: Redding, Red Bluff, CA

This area north of Sacramento jumped up from 17th place in 2017 to ninth, mostly due to higher ozone levels. The report says higher temperatures make it more likely to form and harder to clean up. Too much of it can trigger coughing and asthma attacks and may even shorten life.

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4 / 19

No. 8: Phoenix-Mesa-Scottsdale, AZ

Up three spots this year, the greater Phoenix area has hot, dry weather that keeps the air smoggy for its 4.5 million residents. The number of high ozone days dropped in 2018, compared with 2017. Efforts like the Ozone Campaign -- in which the county air quality department calls on locals to commit to one day of driving less while carpooling and biking more, and skipping drive-thru lines to go inside -- should keep the good work going.

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modesto merced
5 / 19

No. 7: Modesto-Merced, CA

The San Joaquin Valley area has ranked among the nation's top 10 smoggiest areas for years. But 2018 marks its lowest number of bad ozone days yet. This is good news for its 800,000-plus residents, especially the more than 17,000 with pediatric asthma. Because their lungs are growing and they breathe a lot of air while playing outside, air pollution is more likely to hit them harder. This can mean ozone-related problems like reduced lung growth.

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san diego
6 / 19

No. 6: San Diego-Carlsbad, CA

Although it claims stellar weather year-round, California’s Beach City is down a spot on the list. Smog can cloud over the blue skies and foul the crisp ocean breezes here. The area thrives in part due to its cloudless skies, low wind speeds, and warm weather. Levels spike during the summer and early fall.

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7 / 19

No. 5: Sacramento-Roseville, CA

California’s capital city had been on its way down the list, but it moved up three places in 2018. What fueled the jump? Agricultural and freight operations, four major highways, and too many smog-producing vehicles. But the number of unhealthy ozone days here has dropped by more than half since 2000.

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fresno madera
8 / 19

No. 4: Fresno-Madera, CA

An estimated 1 million residents, plus thousands of visitors to nearby national parks, breathe in unhealthy levels of ozone in California’s Central Valley. Like other Golden State cities, weather and geography push the ozone spikes. On the plus side, the region had fewer high ozone days and moved up the list from 3 to 4.  

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visalia porterville hanford
9 / 19

No. 3: Visalia-Porterville-Hanford, CA

Air quality in the gateway to Sequoia National Park has fallen. As a result, the area moved from 4 to 3 in the rankings. This is largely due to the high ozone levels that continue to cover the region and pose a health threat. Weather and geography trap smog and other types of dangerous, dirty air in California’s San Joaquin Valley.

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10 / 19

No. 2: Bakersfield, CA

This Southern California city holds the No. 2 position, just as it has for the 2 previous years. Oil companies and car and truck emissions are to blame for Bakersfield stalling in the rankings. But there has been some progress: This year, the area marked its lowest-ever number of bad ozone days.

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los angeles
11 / 19

No. 1: Los Angeles

The City of Angels once again takes the No. 1 spot for unhealthy air. But it’s making strides. 2018 saw the reached lowest number of bad ozone days ever reported. Laws that lower emissions from power plants, cars, and trucks get the credit.

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12 / 19

Fairbanks, AK and Particle Pollution

This city’s new ranking makes the importance of monitoring clear. Before it upgraded its equipment, there wasn’t enough data for this information. Now, that data reveals that Fairbanks has the highest year-round particle pollution levels in the 2018 report. In 2017, it was at No. 17.

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beautiful lake
13 / 19

Cleanest Cities

Fresh air is in high supply in six U.S. cities, up from four from the last report. A Cleanest City ranking means that town had zero high ozone or high particle pollution days and ranked among the 25 cities with the lowest year-round particle levels. Five locales are repeat rankers, but one joins the list for the first time. 

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14 / 19

Clean Air: Bellingham, WA

New to the list, this area boasts some of the nation’s healthiest air. It’s tied for first for lowest ozone levels and for 24-hour particle pollution. It’s also ranked 166th out of 187 metropolitan areas for annual particle pollution. Located near Puget Bay, the city benefits from brisk winds and a lack of major polluters and industries like refineries that produce emissions.

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Clean Air: Burlington, South Burlington, Vermont

Vermont’s largest city dropped one notch in the rankings, but it’s still among the cleanest. This college town is nestled between Lake Champlain and the Green Mountains. Besides an awe-inspiring landscape, it has a walkable downtown area and plentiful parks. These features aren't just good for whiling away the hours; they also give air quality a boost.

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16 / 19

Clean Air: Casper, Wyoming

Another new addition, Casper ranks third among the nation’s cleanest metropolitan areas for year-round particle pollution, eighth for ozone pollution, and ninth for 24-hour particle pollution. Cheyenne, in the southeast corner of this mountainous, sparsely populated state, topped the list for cleanest cities with regard to year-round particle pollution and scored high on the cleanest cities for ozone pollution list as well.

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honolulu hawaii
17 / 19

Clean Air: Honolulu

It’s home to about 1 million locals and welcomes eight times as many tourists each year. Despite this, the island paradise of Oahu is almost smog-free. It’s near water, so constant breezes whisk pollution out to sea. And there’s a lot of rainfall and lack of heavy industry. Both help keep this beautiful area clean.

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Clean Air: Palm Bay-Melbourne-Titusville, FL

Florida’s Space Coast area is no stranger to the Cleanest Cities List. It’s blessed by nature with a flat landscape and strong winds that don’t give dirty air a chance to linger. This area had no unhealthy air days in 2017. It also ranked among the nation’s cleanest for ozone as well as year-round and short-term particle pollution.

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19 / 19

Clean Air: Wilmington, NC

The state’s Clean Smokestacks Act, which put tough emission standards on coal-fired power plants, did a lot to improve air quality here. Now, this charming coastal town has bragging rights for recording zero unhealthy air days. This is the second year that Wilmington has made the list of cleanest cities. Its appearance makes history for the state: No other city here has ever placed on it.

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Sources | Medically Reviewed on 12/12/2018 Reviewed by Carol DerSarkissian on December 12, 2018


1) ginomaccanti / Getty Images

2) Sylvain Sonnet / Getty Images

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4) miroslav_1 / Getty Images

5) BokicaK / Wikipedia

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American Lung Association: “Children and Air Pollution,” “Ozone,” "State of the Air 2018," State of the Air 2017,” "State of the Air 2016."

511NYRideshare: “Air Quality Information.”

Record Searchlight: “Redding, Red Bluff air quality officials dispute pollution ranking.”

News release, Arizona Department of Environmental Quality.

Queen Creek Independent: “Maricopa County agency begins campaign to combat ozone pollution.”

City of Carlsbad, California: “Air Quality.”

Visit Fresno County: “About Fresno County.”

Visit Visalia: “Visit Visalia.”

Visalia Times Delta: “Unhealthy air across the valley.”

News release, American Lung Association.

The Western Front: “Bellingham Ties for First In Cleanest Air Quality Report.” “Statistics.”

The University of Vermont: “Burlington, VT.”

The Boston Globe: “5 ways to explore Burlington, Vt.”

City of Burlington: “Parks, Recreation, Waterfront.”

University of Wyoming: “Laramie and Surroundings.”

Hawaiian Tourism Authority: "2016 Annual Visitor Research Report."

University of Hawaii, Department of Geology & Geophysics, Ask-An-Earth-Scientist: "Air Quality in Hawaii."

Port City Daily: “Wilmington ranks top of the nation in study on air quality.”

North Carolina Environmental Quality: “Clean Smokestacks Act (CSA).”

Star News Online: “Take a deep breath: Wilmington among US cities with cleanest air.”

Reviewed by Carol DerSarkissian on December 12, 2018

This tool does not provide medical advice. See additional information.

THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional medical advice, diagnosis or treatment and should not be relied on to make decisions about your health. Never ignore professional medical advice in seeking treatment because of something you have read on the WebMD Site. If you think you may have a medical emergency, immediately call your doctor or dial 911.