A new study just released by the Clean Air Task Force (CATF) concludes that diesel fine particle emissions (PM_2.5) from the US fleet directly contribute to the premature deaths of some 21,000 people in the US every year.

CATF commissioned the report, Diesel and Health in America: The Lingering Threat, from Abt Associations, which used methodology approved by the EPA’s Science Advisory Board (SAB) to reach its conclusions. (Full report here.)

It is the size and age of the existing diesel fleet that creates the magnitude of this problem. The increasingly strict EPA regulations on diesel emissions for new vehicles don’t affect the legacy fleet.

The CATF report concludes that a rigorous program of retrofitting for emissions reductions and clean fuels programs could save some 100,000 individuals from premature death over the next 25 years. These are additional lives saved above and beyond the projected impact of EPA’s new engine regulations.

Key findings of the report include:

• Fine particle pollution from diesels shortens the lives of nearly 21,000 people each year. This includes almost 3,000 early deaths from lung cancer.

• The increase in respiratory illnesses associated with diesel PM result in thousands of emergency room visits, hospitalizations, and lost work days. Together with the toll of premature deaths, the health damages from diesel fine particles will total $139 billion in 2010.

• Nationally, diesel exhaust poses a cancer risk that is 7.5 times higher than the combined total cancer risk from all other air toxics.

• In the U.S., the average lifetime nationwide cancer risk due to diesel exhaust is more than 350 times greater than the level EPA considers “acceptable”—one cancer per million persons over 70 years.

• The risk of lung cancer from diesel exhaust for people living in urban areas is three times that for those living in rural areas.

• Reducing diesel fine particle emissions 50% by 2010, 75% by 2015, and 85% by 2020 would save nearly 100,000 lives between now and 2030.

The charts below show the states and metro areas with the highest mortality rates from PM_2.5. Click to enlarge.

A variety of practical strategies exist to reduce diesel particle levels in America: tailpipe retrofits, clean fuels, closed crankcase filtration systems, engine rebuild and replacement requirements, emission specifications for vehicles used in public works contracts, anti-idling ordinances and legislation, truck stop electrification programs, aggressive fleet turnover policies, and more.

The report calls for supplementary programs by cities and states, with support from the Federal government, to encourage and/or to mandate a combination of policies that could easily (from a technology point of view) achieve the necessary fleet-wide reductions.

The variety of actions being taken by California to bring its PM emissions under control are an example.