The average risk of developing cancer as a result of pollution found in the Los Angeles air basin has dropped by more than 50 percent, according to a new report from the South Coast Air Quality Management District.
AQMD officials said the reduction is part of a decades-long improvement of the region’s air quality.
“The significant reduction in cancer-causing substances in the air we breathe over the last 20 years is one of the region’s greatest achievements in pollution control," said Barry Wallerstein, executive officer of the South Coast Air Quality Management District. "In the broader context, the results are frankly pretty remarkable."
The Multiple Air Toxics Exposure Study IV (MATES IV) looked at data collected between 2005 and 2012 and combined measurements of several carcinogenic materials found in the air with toxic emissions inventories and computer modeling to predict cancer risk.
The study estimated that 418 people per million would develop some form of cancer from a lifetime of exposure to air toxins found in 2012-2013. That number is down from the 1,194-per-million-estimate found in the previous MATES III study.
The agency credits the improvement to a number of factors, including monetary incentives to reduce pollution, increased funding for pollution control and better maintenance by industry. Wallerstein stressed that cleaner-running vehicles have greatly contributed to the improvement.
“Incentive programs that help speed up the removal of older vehicles from our fleet and replacing them with modern technology vehicles is having a real significant, positive impact,” he said.
Despite the improvement, Wallerstein said the levels of carcinogenic pollution in the air basin are still unacceptable.
“The MATES IV study documents a major success in battling air toxics, and at the same time is a call for a sustained effort to further reduce carcinogens in our air,” he said.
The study found that 68 percent of the total cancer risk comes from particulate emissions from diesel-powered trucks and other vehicles.
The ports of Long Beach and Los Angeles continue to have the greatest cancer risk despite seeing some of the greatest relative reductions. Cancer estimates at the ports are at 1050 per million over a 70-year lifetime of exposure.
Though the overall amount of carcinogenic pollution has decreased in the region, future estimates of cancer risk could be higher because the California Office of Environmental Health Hazard Assessment is reevaluating the cancer risk caused by air toxins. The agency is expected to release new cancer-risk guidelines in early 2015 that show air pollution is an even greater cause of cancer than previously understood. Those guidelines will increase estimates cancer risk by an average factor of 2.7.
“While it’s a huge success story that we’ve brought the risk down, new information is suggesting that these air toxics have a larger effect than previously believed,” said Philip Fine, assistant deputy executive officer for the AQMD.