Diesel exhaust contributes more to a component of smog than gasoline-fueled cars, according to a new UC Berkeley study.
The study, published today in the Proceedings of the National Academy of Sciences, elucidates the contributions to air pollution from the two types of fuel emissions. The authors estimate that diesel exhaust is responsible for 65-90 percent of a region’s vehicular-derived SOA,(Secondary Organic Aerosol) depending upon the relative amounts of gasoline and diesel used in the area.

SOA contributes to respiratory problems and poor air quality, so pinpointing the major sources of the pollutant is important in evaluating current and future policies to reduce smog in the state.

“We can now say that, while both motor vehicle sources are important for these ‘secondary’ particles, diesel is responsible for a larger portion, especially in regions such as the San Joaquin Valley with a lot of diesel use,” said study principal investigator and professor Allen Goldstein.

Diesel vs gasoline