LOS ANGELES — By at least one measure, Southern California’s air is getting healthier.
The risk of cancer from airborne pollutants has dropped by more than 50 percent on average since 2005, according to a study released Thursday by the region’s air quality regulators.
Concerted efforts to reduce emissions from trucks and other vehicles account for much of the drop.
The findings may not surprise residents of the region long cited for poor air quality. Unlike previous decades, it’s now uncommon for smog to brown out the mountains that crisscross the region.
Still, risks persist from toxic pollutants such as diesel particulate matter and benzene.
Those risks are still some of the highest in the nation, said Philip Fine, assistant deputy executive officer with the South Coast Air Quality Management District, which conducted the study.
Exact comparisons between Southern California and other metropolitan areas are not possible because other areas compute risk differently, according to officials with the air district.
For every 1 million people who live in Southern California for 70 years, 418 would be expected to develop cancer because of the current levels of toxic air — compared with 1,194 extra cases based on 2005 air quality, according to the study.