More Than Half Of The U.S. Is Living With Unhealthy Pollution Levels

If the apocalyptic photos of smog blanketing Beijing last year seemed like a world away, think again.

The American Lung Association released its annual "State of the Air" report Wednesday and revealed that if you live in the U.S., chances are you're living among some seriously unhealthy air.

The report, which covers data collected from 2012 to 2014, measures year-round particle pollution , the average amount of tiny solid and liquid particles found in the air over a year; short-term particle pollution , harmful hours- or dayslong spikes in particle pollution; and ozone pollution, also known as smog, which is created when gases that come out of tailpipes, smokestacks and other sources come into contact with sunlight. 

Breathing in air contaminated with any of these pollutants is associated with early death, cardiovascular harm, respiratory disease and cancer -- yet there are nearly 20 million people in the U.S. living with unhealthful levels of all three.

“Everyone has the right to breathe healthy air. ... We simply must do more to protect the health of Americans,” Harold P. Wimmer, the national president and CEO of the American Lung Association, said with the release of the report.  

More Than Half Of Americans Live In Counties With Unhealthy Pollution Levels 

About 52 percent of the population, or 166 million Americans, are living in the 418 counties where they're exposed to unhealthful levels -- ones that could shorten life or cause lung cancer -- of either ozone pollution or short-term or year-round particle pollution.

This is an uptick from last year's report, which found that 4 in 10 Americans, totaling nearly 138.5 million people, were living in such conditions. The higher number is explained by an increase in short-term particle pollution -- often a direct result of weather events like drought and wildfires -- and a stricter definition of healthy ozone levels adopted by the Environmental Protection Agency, the ALA said.  

Overall, the report observed a reduction of ozone and year-round particle pollution across the U.S. 

California Is The Capital Of Bad Air Quality

For all three top 10 lists of places with the worst air quality, California metropolitan areas populate more than half the list. 

Top 10 U.S. Cities Most Polluted by Short-Term Particle Pollution

1. Bakersfield, California
2. Fresno-Madera, California
3. Visalia-Porterville-Hanford, California
4. Modesto-Merced, California
5. Fairbanks, Alaska
6. Salt Lake City-Provo-Orem, Utah
7. Logan, Utah-Idaho
8. San Jose-San Francisco-Oakland, California
9. Los Angeles-Long Beach, California
10. Missoula, Montana

Top 10 U.S. Cities Most Polluted by Year-Round Particle Pollution

1. Bakersfield, California
2. Visalia-Porterville-Hanford, California
3. Fresno-Madera, California
4. Los Angeles-Long Beach, California
5. El Centro, California
6T. Modesto-Merced, California
6T. San Jose-San Francisco-Oakland, California
8. Pittsburgh-New Castle-Weirton, Pennsylvania-Ohio-West Virginia
9. Harrisburg-York-Lebanon, Pennsylvania
10. Louisville-Jefferson County-Elizabethtown-Madison, Kentucky-Indiana

Top 10 Most Ozone-Polluted Cities

1. Los Angeles-Long Beach, California
2. Bakersfield, California
3. Visalia-Porterville-Hanford, California
4. Fresno-Madera, California
5. Phoenix-Mesa-Scottsdale, Arizona
6. Sacramento-Roseville, California
7. Modesto-Merced, California
8. Denver-Aurora, Colorado
9. Las Vegas-Henderson, Nevada-Arizona
10. Fort Collins, Colorado

What's going on in Bakersfield, which tops two of the lists and comes in second on the other? The central California farming town, which experienced worse pollution in all three categories compared to last year's report, is a victim of geography and recent high temperatures . Surrounded by mountains on all sides that trap pollution, heat mixing with soot and ozone combine to create smog .

Extreme Weather Events Driven By Climate Change Are Making Pollution Harder To Combat

While the report commends the Clean Air Act for improving year-round particle pollution, the spike in short-term particle pollution is a result of weather events caused by climate change. 

"The rise in short-term particle pollution provides current examples of how major changes in drought and rainfall are already affecting public health," the report explains. "Wildfires and drought, along with high use of wood-burning devices for heat, coupled with stagnant weather patterns that concentrated pollution in some areas, contributed to the extraordinarily high numbers of days  with unhealthy particulate matter in 2012–2014."

Short-term particle pollution spikes were especially evident in Western states, namely California, where the ongoing drought led to some of the worst wildfires in state history last fall, sending storms of particulate matter into the air. Dry soil also allows particle pollution to thrive. 

Because of particle pollution, seven of the 25 most-polluted cities had their highest number of unhealthy days  on average ever reported, the ALA found. 

It's Not All Bad News

A majority of the most polluted areas saw improvements in air quality compared to last year's report. Sixteen of the top 25 most-polluted metropolitan areas experienced their lowest year-round particle pollution levels in the report's 17-year history.

Four metropolitan areas were ranked as the top 25 cleanest in all three pollution categories: Burlington-South Burlington, Vermont; Elmira-Corning, New York; Honolulu, Hawaii; and Salinas, California. Unfortunately, that's a slight downgrade from last year, when six cities made the cut. 

Los Angeles has held the title for worst ozone pollution in the ALA's report every year, and while it maintained that streak, it did manage to claim a personal best. The metropolitan area reported its best air quality ever, with a record-low average for year-round particles and the fewest high-ozone and high-particle days ever recorded.