--- title: The 10 Most Polluted Cities in America description: Bakersfield, Merced and Fresno top the American Lung Association's list of cities with the most persistant air pollution in the country in 2013 canonical: https://time.com/43830/the-10-most-polluted-cities-in-america/ author: Bryan Walsh article:opinion: false article:content_tier: free article:published_time: 2013-11-06T00:51:54.000Z article:modified_time: 2026-05-11T05:08:30.719Z article:section: Science og:title: The 10 Most Polluted Cities in America og:description: Bakersfield, Merced and Fresno top the American Lung Association's list of cities with the most persistant air pollution in the country in 2013 og:url: https://time.com/43830/the-10-most-polluted-cities-in-america/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltde093bcdab65f2d0/6988d9b9bc6cfc69913e2a3c/time-logo.jpg?branch=production og:image:width: 1200 og:image:height: 675 og:image:alt: TIME og:type: article twitter:card: summary_large_image twitter:title: The 10 Most Polluted Cities in America twitter:description: Bakersfield, Merced and Fresno top the American Lung Association's list of cities with the most persistant air pollution in the country in 2013 twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/bltde093bcdab65f2d0/6988d9b9bc6cfc69913e2a3c/time-logo.jpg?branch=production --- # The 10 Most Polluted Cities in America  by [Bryan Walsh](https://time.com/author/bryan-walsh/)  ## Bryan Walsh Nov 6, 2013 12:51 AM UTC  by [Bryan Walsh](https://time.com/author/bryan-walsh/)  ## Bryan Walsh Nov 6, 2013 12:51 AM UTC ### #1 (tie): Bakersfield, CA  In this Dec. 18, 2012 photo, oil pumping stations and electrical transmission lines clutter the horizon over the dry Kern River in Bakersfield, Calif. Despite an economy on the upswing, business leaders say they often have trouble luring to the region job seekers who fail to look past scenes like this. (AP Photo/Tracie Cone) Tracie Cone—AP Smog has been a persistent problem for years in Bakersfield, where over 60,000 residents have asthma, and where ozone air quality is considered unhealthy or worse for nearly two-thirds of the year. But there is good news—air pollution has improved over the past decade even as the population has increased. ### #1 (tie): Merced, CA  The University of California Merced prepares on Thursday, May 15, 2009, for the University's graduation and a visit by the First Lady Michelle Obama in Merced, California. (Marci Stenberg/Merced Sun-Star/MCT) Marci Stenberg—Merced Sun-Star/MCT/Getty Images Merced doesn’t suffer from the particularly high air pollution days that other cities on the list do, but it does have year-round average levels of particulates that are unhealthy. Some of that pollution may be do to drift from the more heavily populated Bay Area, which sites to the west of Merced. ### #3: Fresno-Madera, CA  The sun rises on Tuesday, July 8, 2008, over the Fresno, Calif. skyline amid a haze. High temperatures in the Central Valley has contributed to poor air quality in the area. MARK CROSSE/THE FRESNO BEE Mark Crosse—The Fresno Bee/AP The Fresno area doesn’t have the worst air pollution on average, but it does have some of the highest levels of very bad days—when it’s polluted in Fresno, it’s really polluted. Nearly a quarter of the greater Fresno-Madera population suffers from some sort of cardiovascular disease, which can be connected to air pollution. Rapid population growth over the past decade has intensified the problem. ### #4 (tie): Hanford-Corcoran, CA  California State Flag Against a White Cloud Sky WilliamSherman—Getty Images Located in the San Joaquin Valley, Hanford is at the heart of the most air-polluted region in the country. Asthma is highly prevalent in Hanford, as are high levels of ozone and particulate pollution. For all the attention paid to big cities like Los Angeles or Pittsburgh, the air is often worse in smaller cities like Hanford. ### #4 (tie): Los Angeles-Long Beach-Riverside, CA  Downtown Los Angeles is visible through a light layer of smog from Mount Lee in Los Angeles, Calif., March 18, 2008\. (AP Photo/Don Ryan) Don Ryan—AP L.A. isn’t anywhere near as bad as it was in the 1960s and early 70s, when smog alert days were a daily fact of life. Cleaner car engines have helped reduce those emissions. But smog and other forms of air pollution are still a problem in the L.A. metro area, while Long Beach experiences serious air pollution from one of the biggest maritime ports in the world. ### #6: Modesto, CA  Carl Skaggs Modesto is in California’s Central Valley, one of the most productive agricultural areas in the U.S., but also one of the most polluted. High ozone days remain a major problem in Modesto, where a combination of geography and emissions from cars and industrial agriculture add up. A little less than 10% of the population has asthma. ### #7: Visalia-Porterville, CA  Southern California Edison (SCE), Porterville Solar array, built from a total of 29 426 panels, can produce 6.7 megawatts (MW) which is enough energy to power 4,300 homes, in Porterville, California, U.S., on Thursday, February 17, 2011\. Photographer: Ken James/Bloomberg Ken James—Bloomberg/Getty Images Ozone pollution a major problem in the Visalia area, where some two-thirds of the days between 2009 and 2011 featured unhealthy levels of ozone. Particulate pollution doubled in Visalia over the last six years, and asthma rates remain extremely high. ### #8: Pittsburgh-New Castle, PA  The Mt. Oliver neighborhood stands before the skyline of Pittsburgh, Pennsylvania, U.S., in this aerial photo taken on Friday, April 9, 2010\. Metropolitan areas in the U.S. with concentrations of manufacturing posted some of the biggest declines in population since 2000, according to government data. Pittsburgh showed the second-biggest population decline, losing about 76,000 residents. Photographer: Andrew Harrer/Bloomberg via Getty Images Andrew Harrer—Bloomberg/Getty Images Pittsburgh isn’t the environmental hellscape it was during the city’s height as a steel producer, when the air was so full of particulates that laundry hung out to dry would turn black on the line. But Pittsburgh still has serious problems, in part because the city is downwind from many Midwestern coal plants. A quarter-million residents have been diagnosed with asthma. ### #9: El Centro, CA  A man drives a tractor past recently planted spinach fields Thursday, Oct. 12, 2006 in El Centro, Calif. After the recent E. coli outbreak that killed three people and sickened nearly 200 others nationwide, spinach farmers face uncertainty for how much demand there will be for their winter crop. (AP Photo/Chris Park) Chris Park—AP El Centro in southern California had 49 days when the ozone level was unhealthy for sensitive populations. Much of the city’s pollution is due to vehicle emissions, though the city has begun to convert city streets into pedestrian areas. Still, nearly 15,000 residents have asthma in a city of about 177,000. ### #10: Cincinnati, OH-Middletown, KY-Wilmington, IN  General view of the Cincinnati skyline prior to the Cincinnati Bengals NFL week 8 football game against the Miami Dolphins on Sunday, October 31, 2010 in Cincinnati, Ohio. The Dolphins won the game 22-14\. (AP Photo/Paul Spinelli) Paul Spinelli—AP The three Midwestern cities tie for year-round particulate pollution, thanks largely to industry and the burning of coal, which provides the bulk of electricity in the region. Cincinnati is improving, however—the number of days with high ozone levels fell by ore than half between 1996-1998 and 2009-2011. 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