The report contains data between 2007 and 2009.
All Bay Area counties stayed constant or showed improvement in ozone pollution compared to 2010 data, except for Napa County which showed a slight increase in unhealthy days, the report states.
All counties showed improvement in particulate pollution compared to last year, except for Alameda and Solano counties, according to the report.
Ozone pollution is from smog, created when heat and sun combine with organic compounds and nitrogen oxides present in tailpipe emissions. Ozone pollution improved in Alameda and Santa Clara counties between 2007 and 2009, according to the report.
Particulate pollution comes from diesel burning trucks, buses, trains that transport goods, and from the Port of Oakland, the American Lung Association's regional air quality director Jenny Bard said.
Contra Costa, Solano and Santa Clara counties got an "F" grade for ozone and particulate pollution, Bard said.
"Air pollution doesn't know boundaries. "Their geography, population and the prevailing winds are conducive to pollution there," Bard said.
Winds blowing in from the Pacific Ocean lift the Bay Area's coastal counties' pollution into the valleys of those counties, and the Sacramento and the San Joaquin valleys. Coastal counties have less ozone pollution.
In winter, the particulate pollution in the cooler coastal counties comes from wood burning stoves.
"A lot has to do with us being on the coast and having smaller populations. We are still driving though and burning wood and out pollution goes to other areas. We need to do more to reduce air pollution," said Bard, who is based in Santa Rosa.
Over the past decade, however, the Bay Area, reduced ozone pollution 70 percent and particulate pollution by 60 percent, the American Lung Association said.
Marin, Sonoma and San Francisco counties made the list of the country's cleanest counties regarding ozone pollution and Sonoma, Monterey and Santa Cruz counties were among the cleanest counties in the country regarding particulate pollution over a 24-hour period, Bard said.
Bard said Solano county claims Interstate Highway 80 contributes to its pollution levels, but the county did show some improvement.
The pollution levels have health effects on people with lung and heart disease and can lead to premature death, Bard said. Even children whose lungs are not fully developed suffer, she said.
The Bay Area has 19 percent of the state's population and 15 percent of California's pollution emissions, according to the report.
