Story highlights California cities were some of the worse air pollution offenders

Cities in Vermont, Hawaii and New York had some of the cleanest air

April 22 is Earth Day

(CNN) Rough day at work? Step outside and take a deep breath -- err, maybe not, depending on what city you're in.

If you're in Los Angeles, you'll probably want to step back inside the office. The sprawling California city is among the worst air pollution offenders in the United States, according to the American Lung Association.

Just before Earth Day, the association released its 2016 State of Air report . The findings reveal more than 50% of Americans live in areas with unhealthy levels of particle pollution, tiny solid and liquid particles floating around the air we breath, or ozone pollution, harmful gases that react to sunlight.

"Ozone pollution is a powerful pollutant," Paul Billings, senior vice president of advocacy at the ALA told CNN. "Breathing it in is like a sunburn of the lungs. It can cause coughing and wheezing in healthy adults."

Heavy road traffic and a busy trade port are major contributors to Los Angeles' poor air pollution. The city joins 12 other counties that failed all three air pollution tests by the ALA. The report analyzed ozone, short-term and year-round particle pollution.