A longshoreman readies a container at the APL Terminal at the Port of Los Angeles ( AP Photo/Damian Dovarganes)

A multi-year study conducted by the South Coast Air Quality Management District has found that cancer risk from air pollution is down overall by 8 percent. However, some areas of the region have an increased risk.

Increases of 17% were found around the port areas in Long Beach and Los Angeles. Slight increases were also found in areas of Riverside County probably due to increased truck traffic warehouse development as by-products of the growth in trade at the ports.

"About 84 percent of all cancer risk from air pollution is due to diesel exhaust from trucks, trains, ships, locomotives and other diesel equipment," stated the AQMD's statement on the study. "The remaining risk is due to toxic emissions from gasoline-powered motor vehicles, businesses and industrial facilities."

A clean truck program that begins in October for the ports of LA and Long Beach will "upgrade their aging fleet of about 16,800 mostly dilapidated rigs that produce much of the diesel pollution in Southern California," reports the LA Times. The trucking industry fought it in court saying it "would lead to place an unconstitutional and unfair economic burden on port truckers." A judge tentatively allowed the program to go through on Monday.

"Cancer risks from air pollution are still far too high in the Southland," said Barry Wallerstein, executive officer of the South Coast Air Quality Management District. "The study results show that we need to continue pursuing all feasible measures to reduce toxic emissions."