A new California Air Resources Board report based on a U.S. EPA peer-reviewed study concluded that there is a causal relationship between exposure to fine particle pollution and premature death.

The report found that about 9,000 people in California die prematurely each year as a result of exposure to fine particle pollution.

"There is no question particulate pollution is causing premature deaths here in California and nationwide," said ARB Chairman Mary Nichols. "This study is further evidence that we are on the right track, and ARB will continue to work with truckers and equipment owners to clean up diesel emissions, improve our air quality and protect public health. ARB is committed to reducing this staggering statistic because one premature death is one too many."

CARB's report estimated that 9,200 premature deaths in California are associated with fine particulate pollution on an annual basis, with a statistical range from 7,300 to as high as 11,000 premature deaths each year. California has the most extensive particulate monitoring network in the nation.

Fine particle pollution, smaller than 2.5 microns, is the product of a variety of sources including particles in the exhaust of diesel engines, CARB says. The report says the relative contribution of particulate matter 2.5 from transportation compared to sources such as power plants is much greater in California, but the state still regulates emissions from both sources.

However, the report points out that California is less industrial than other parts of the nation, so more emission reductions must be achieved through CARB regulations of mobile sources, including trucks.

The CARB report and its methodology were based on recent assessments by the U.S. EPA, required as part of the federal agency's periodic review of the national air quality standards for fine particle matter.

This initial U.S. EPA review was followed by a related risk assessment report released in June that estimated premature deaths nationwide from exposure to fine particulate pollution.

CARB used the same methodology and risk factors the peer-reviewed U.S. EPA report used and applied it to the entire state, drawing on California-specific data from 90 fine-particulate monitoring stations to estimate the number of premature deaths that can be linked to this pollution.

To view the CARB report, click here.