Phoenix named 5th most polluted city in U.S., study says

PHOENIX - Phoenix is one of the most polluted cities in the United States, according to a new report released by the American Lung Association.

According to the organization's annual State of the Air report, the Phoenix-Mesa area was the 5th most polluted for ozone for the second year in the row.

The Valley also ranked 7th in year-round particle pollution and 13th in short-term particle pollution.

Overall, Maricopa County was the 7th worst among counties nationwide for ozone pollution.

Experts say heat and sunlight contribute to the creation of ozone, which gets trapped in the Valley. Wildfires also increase particle pollution.