SACRAMENTO (AP) — California officials say the concentration of seven cancer-causing pollutants dropped steeply between 1990 and 2012, and they believe tougher pollution rules are behind that.
The Sacramento Bee reports that the California Air Resources Board published the study in the Environmental Science & Technology journal this month. It shows large declines in carcinogens like benzene, used in motor fuels and other products, and perchloethylene, which is used in dry cleaning.
The board attributes the decline to measures like requiring filters for diesel trucks and purchasing new, cleaner truck fleets. The officials also offered grants to encourage dry cleaners to use greener methods.
The concentration of benzene fell about 90 percent over the 23-year period, even though population grew and the use of diesel vehicles increased.