CORRECTION: Due to incorrect information provided by New York University, estimates on the number of deaths, illnesses and sick days caused by air pollution in the Los Angeles-Long Beach-Glendale area were incorrect in an earlier version of this story.

As Southern California continues to struggle through this summer’s unrelenting smog, a study released Wednesday, Aug. 10, gives a stark reminder of why air quality matters.

Researchers believe that hundreds of people die each year because of Southern California’s poor air quality. Pollution levels routinely exceed the levels deemed safe by health professionals.

In the Los Angeles-Long Beach-Glendale area, about 1,341 people are estimated to die each year because of bad air.

That makes the L.A. area’s air quality the deadliest in the nation.

The Riverside-San Bernardino-Ontario metropolitan area was second worst, with about 808 people estimated to die annually because of air pollution.

The Santa Ana-Irvine area had 64 estimated deaths from air pollution.

The study was conducted by the American Thoracic Society, a group of health-care professionals that focuses on understanding pulmonary diseases, critical illnesses and sleep-related breathing disorders, and New York University’s Marron Institute of Urban Management.

Nationally, the deaths were estimated at 9,320 a year, which is comparable to the number of lives lost annually to drunken driving.

Check the air quality in your area

The study’s lead author, Kevin Cromer, a professor at the NYU institute, said by telephone that he hopes the results will raise public awareness and better inform policy makers.

“We are just providing previously unavailable information that can help air quality managers and cities make more meaningful decisions,” said Cromer, who has expertise in population health and environmental medicine.

The study was based on air pollution data for both fine particle and ozone levels in U.S. metropolitan areas recorded in 2011, 2012 and 2013.

The numbers of deaths and illnesses were then estimated through computer analysis that took into account epidemiological studies linking various health effects to air pollution exposure.

The researchers noted that they believe their results are conservative. They did not count deaths from cancers that take decades to develop or deaths from the exacerbation of other chronic illnesses such as diabetes.

Cromer and his colleagues also created a website,, that allows users to input zip codes to learn the estimated numbers of deaths and illness in regions throughout the nation.

Dr. Ahmet Baydur, a pulmonary expert and professor of clinical medicine at the University of Southern California’s Keck School of Medicine, said the people most at risk are those whose lungs already are damaged by smoking and people with emphysema, chronic bronchitis, and severe asthma.

Of particular concern are people who need to treat themselves with oxygen from portable oxygen tanks, he said.