According to the American Lung Association (ALA), over 50% of Americans live in counties that have unhealthy levels of ozone or pollution particulates in the air. Here's a list of the highest risk areas in the United States!
Los Angeles- Long Beach, CA
It's gorgeous and sunny, but Los Angeles-Long Beach is ranked #1 out of 228 metro areas in high ozone days and #4 for annual particle pollution out of 171 metro areas by the ALA.
Image via: Flickr