"Truckers want tougher enforcement and point to competitors who violate state rules to install filters or upgrade to cleaner engines."
"As state air pollution officials step up inspections of diesel exhaust from big rigs, some of their best allies are truckers themselves.
They are pushing the Air Resources Board to enforce pollution rules more aggressively for trucks in advance of a Jan. 1 deadline.
Truckers are also the No.1 tipsters, placing anonymous calls and sending emails to finger competitors they say are gaining an unfair advantage by not upgrading their engines or installing expensive filters that capture harmful diesel particulates before they are released into the air.
Diesel exhaust is the worst remaining pollution source on roadways. It contains smog-forming nitrogen oxides and fine particles — soot — that lodge deep in the lungs and are linked to lung and heart disease, asthma and cancer. Diesel soot was classified as a toxic air contaminant by the state in 1998."