SAN DIEGO -
In San Diego County, it's getting easier to just breathe, but it depends on which ZIP code you live in, according to a study by 10News and the research group the Equinox Center.
According to the Equinox Center, the latest data from the Environmental Protection Agency shows there were 28 days in 2009 classified as unhealthy air quality days for older adults and children -- down from 40 during the year before.
Ann Tartre, executive director of the Equinox Center, said the recession has led to fewer air pollutants.
"There are fewer people on the roads going to jobs, less construction and less business traffic, which means fewer air emissions," said Tartre.
While San Diego ranks well above places like Los Angeles in terms of air quality, the study shows it lags behind cities like San Francisco. According to the study, relatively fewer public transportation options are a factor.
"The biggest factor is related to transportation-related pollution," said Tartre.
How much a concern air quality is depends on which ZIP code you live in.
The Equinox Center looked at child asthma hospitalization rates, with lower rates considered an indicator of good air quality. The lowest rates hugged the coast and were scattered in the North County and rural areas.
The study showed high hospitalization rates were found in ZIP codes in San Diego and the East County, where hotter temperatures can create more smog.
The highest rates were found in eastern Chula Vista, Lemon Grove and two high-traffic ZIP codes in central San Diego -- the Barrio Logan area of the 92113 ZIP code, which is close to industry and a Navy base, and the 92123 ZIP code, which includes Montgomery Field and is bordered by three highways.