Soot causes lung problems, period
Lois Henry's Oct. 21 column, "State air board can't ignore credibility problems," is another attempt to change the conversation about the reason the California Air Resources Board is working to cut diesel emissions: public health.
Residents of Bakersfield endure some of the nation's worst air quality while asthma levels are on the rise, particularly in children. Fine particulate matter that can be breathed deep into the lungs is widely recognized by the scientific community to be a cause of asthma exacerbations, hospitalization for heart and lung problems, and even premature death. Diesel particulate matter, or soot, is the most pervasive toxic air contaminant in California and is considered particularly hazardous because truck drivers and railroad workers exposed on the job have been shown to have increased risk of lung cancer and heart disease.
CARB has already adopted regulations to clean up trash trucks, transit buses, cargo-handling equipment, port trucks, harbor craft and ship engines, as well as diesel fuel itself. Isn't it time that diesel trucks and construction equipment do their fair share to clean the air as well?
To ease the cost of compliance for smaller firms, the board rule gave companies subject to the off-road diesel equipment rules an extended deadline to meet the standards, and recently changed the rule to give even more time for all companies to comply.
Any attempt to regulate a compound as widespread in our economy as diesel soot must be based on clear and convincing scientific evidence that it is a health threat. It should come as no surprise that the science continues to be debated, or that advocacy organizations will continue to try to discredit or support the studies that the board relied on in making the finding that diesel emissions constitute a toxic health threat.
Research on the relationship between airborne particles (like diesel soot) and health effects has been going on for many years and will no doubt continue as scientists attempt to understand and refine the exact nature and degree of the problem.
The report that Henry criticizes is a compilation and evaluation of current research reported in the scientific literature. It was subjected to a rigorous independent scientific peer review prior to its release. After CARB management was made aware of the fact that a career employee who played a key role in preparing that report had falsely claimed to have completed his Ph.D. from an accredited university, CARB asked the same group of 10 external experts to reconsider their prior comments in light of this employee's bad judgment. All nine that responded confirmed their original comments on the report. (The employee was also subject to a disciplinary proceeding.)
We support continued debate based on real science and data and believe it can only strengthen our program. Based on the record we have reviewed, we believe that the evidence supports the urgency of reducing public exposure to diesel soot (as do many public agencies and health organizations worldwide), and we continue to support reasonable, technically feasible regulations as well as financial incentives to do so.
John R. Balmes, M.D., has served on the California Air Resources Board since 2007 as an expert on the impacts of air pollution on public health, and is professor of medicine at UC San Francisco and professor of environmental health sciences at UC Berkeley.
