Study: LA is Most Polluted City in the Country

According to the American Lung Association, Los Angeles is the most polluted city in the country.

"There are a large number of people and cars that live in those areas," said Karen Magliano from the California Resources Board. "There are also challenges just with the geography and the weather patterns that tend to allow air pollution to accumulate."

Although the city's particle pollution has dropped, the ozone levels are on the rise. Ozone is a gas in the upper atmosphere that prevents harmful radiation from reaching the earth. A mixture of smog and ground-level ozone can cause asthma, cancer, heart and lung complications.

The study said the city has violated federal health standards for ozone, with a total of 122 days in a year. Los Angeles isn't the only one that makes the list in California.

The top five cities with the worst air quality in the country are in California. After LA comes Visalia, Bakersfield, Fresno, and Sacramento.