The California Air Resources Board did pass the diesel emissions standards on Friday. The standards will be the toughest in the nation and will require extensive retrofitting of heavy diesel trucks and buses. Some older models will have to be phased out entirely.
Around a million trucks and buses will be retrofitted or replaced. Retrofits will require smog filters or cleaner engine technology beginning in 2011. By 2014, all trucks and buses must have soot filters. By 2023, no truck or bus will be allowed to be more than 13 years old unless it has special equipment to cut nitrogen oxide emissions.
This approval comes in the same week that California also passed the most stringent greenhouse gas emissions laws in the nation. Reducing diesel soot emissions will improve human health, air quality, and also fight climate change.