The overall collective risk of cancer via exposure to 7 toxic air contaminants in California has declined by an incredible 76% since comprehensive air quality regulations went into effect there back into 1990, according to a new study from the California Air Resources Board.
To be more specific here, the study examined cancer risk for the years of 1990 through 2012 as associated with various air contaminants. Out of the 7 contaminants investigated, diesel particulate matter is known to be the most relevant to cancer risk — such contaminants are released into the air primarily as a result of truck and bus operation.
While the contaminant wasn’t measured directly, a surrogate method was used to determine that concentrations of diesel particulate matter fell by 68% between the years of 1990 and 2012 — this in spite of the fact that the state’s population grew by 31%, the gross state product rose by 74%, and diesel vehicle miles traveled increased by 81%.
Green Car Congress provides more:
The nearly 70% drop in DPM coincided with actions taken over the years, beginning in the 1990s, to reduce diesel emissions. In the 1990s, California adopted a reformulated diesel fuel program; started a heavy-duty diesel truck roadside inspection program; implemented particle pollution standards for urban transit buses; and established standards for off-road diesel engines. In 2006, California began requiring ultra-low-sulfur diesel fuel.
Following the establishment of California’s statewide Truck and Bus Rule in 2008, California began requiring diesel particulate filters on trucks, reducing diesel particulate matter from the exhaust gas of diesel engines.
Based on monitoring data, concentrations of benzene; 1,3-butadiene; perchloroethylene; and hexavalent chromium declined 88–94%. (The reduction of benzene and 1,3-butadiene was largely the result of California gasoline reformulation in 1996, ARB said.) Also, the ambient and emissions trends for each of these four TACs were similar. Formaldehyde and acetaldehyde, which are formed in the air photochemically from volatile organic compounds (VOCs), declined only 20–21%.
With improving regulations, the risk of cancer in the state is expected to continue dropping notably, according to the researchers involved in the new findings — “improvements to regulations” being a reference mostly to tighter controls on diesel truck and bus operation, as well as to the operation of diesel equipment at/in rail yards and ports.
The new research was published in the ACS journal Environmental Science & Technology.
Of course, it would be much better if regulations were followed as required. On that matter, I direct you here: