The Golden State has taken another step toward reducing its serious air pollution problem.
The California Air Resources Board (ARB), a department of the California EPA, adopted a regulation that will further reduce air pollution from the state's transit buses. The regulation will also require some fleet operators to start using zero-emission buses (ZEBs) in three years.
The regulation, which in 2002 starts its phase-in, affects about 8,500 buses at approximately 75 California transit agencies.
According to ARB, the regulation moves forward in several steps over the next 10 years, requiring cleaner engines, cleaner diesel fuel, retrofit to reduce exhaust particulate matter (PM) emissions from older diesel buses, use of ZEBs and reduced exhaust PM and nitrogen oxides (Nox) from new diesel engines.
Diesel exhaust PM contributes to mortality and contains substances known to cause cancer, while Nox contributes to ozone, the main harmful component of urban smog.
"This regulation cuts air pollution where it is most troublesome -- in the heart of our cities where 90 percent of Californians live," said ARB Chairman Dr. Alan Lloyd.
The regulation allows transit agencies the flexibility of choosing between either a diesel or alternative fuel "path" to lower air emissions.
Agencies may choose to use low-emission alternative fuels, such as compressed or liquefied natural gas, propane, methanol, electricity, fuel cells or other advanced technology.
Continued use of diesel brings with it a requirement to use low-sulfur diesel fuel beginning July 1, 2002, and cut emissions from new diesel buses by another 75 percent beginning in 2004.
An even lower Nox standard applies to both diesel and alternative fuel bus engines sold to California transit agencies starting in 2007.
In addition, for both diesel and alternative fuel paths, a Nox fleet average of 4.8 begins in 2002, which will require some transit agencies to retire their oldest, highest polluting buses.
When the requirements are fully implemented, all transit buses will be smoke-free and will emit less smog forming emissions, according to ARB.
"The regulation is designed to bring quick, near-term emissions reductions and long-term, near-zero emission benefits," said Lloyd.
ARB staff calculates that the new transit bus rules, combined with normal fleet turnover, will bring statewide reductions of seven-tons-per-day of Nox and 12 tons-per-year of PM by 2020.