Bus Filters Remove Tons of Soot from Bay Area Air

Historic Diesel Cleanup Program for 1,700 Buses

SAN FRANCISCO, Sept. 26 -- Bay Area residents can expect the region's normally excellent air quality to become even better in the years ahead, as the Metropolitan Transportation Commission (MTC), the Bay Area Air Quality Management District and the area's transit systems near completion of an unprecedented diesel cleanup program.

Through the Clean Diesel Bus Program, more than 1,700 diesel buses from 13 Bay Area transit districts are being retrofitted with diesel exhaust filters. Combined, these high-tech emission control filters annually capture more than 50 tons of harmful particulate matter and 436 tons of oxides of nitrogen (NOx) that otherwise would have been emitted by buses into Bay Area air.

Diesel particulate matter is a toxic air contaminant that can cause lung disease and cancer. NOx, another component of diesel exhaust, are a precursor to ozone, which can cause respiratory disease, according to the California Air Resources Board.

The Air District, MTC and the region's transit districts provided funding for implementation of the clean diesel bus program. Installation of the devices, which are manufactured by San Leandro-based Cleaire Advanced Emission Controls, began in 2003. Nearly 1,400 exhaust filters for Bay Area buses already have been delivered. Most of the remaining 340 exhaust filters are scheduled for installation by the end of 2006.

"The Air District is committed to achieving clean air to protect the public's health and the environment," said Jack Broadbent, Executive Officer of the Bay Area Air Quality Management District. "Technology can play an important role in reducing emissions from mobile sources and help the Bay Area to attain and maintain air quality standards. This project represents a step towards reducing emissions from buses in our region."

While the 13 Bay Area transit districts participating in the bus retrofit have purchased some clean new buses, most of the exhaust reduction is coming from the installation of diesel exhaust filters on existing buses that have years of life remaining. The devices capture 85 percent of the particulate matter and reduce 25 percent of the NOx created by the buses' engines. Each installation costs about $18,000, compared to $140,000 or more for a new bus.

"The installation of the exhaust filters goes a long way to improving air quality," said Steve Heminger, executive director of MTC. "Retrofitting buses is a cost-effective way to clean our air."

On an average Bay Area bus, each diesel exhaust filter reduces particulate matter emissions by 59 pounds per year and reduces NOx emissions by 515 pounds per year. "We are proud to play a role in removing diesel soot from Bay Area air," said Kevin Shanahan, president of Cleaire (pronounced klee-air). "This is a program and a practical solution that really works."

San Francisco Muni is leading the way for the Bay Area by retrofitting 424 of its diesel buses. AC Transit will have 416 diesel exhaust filters when its retrofit program is complete in December 2006. The table below details the status of the diesel filter installation program for each transit district:

  Fleet                                            Delivered         To Go

  San Francisco Muni                                   424              0
  AC Transit                                           275            141
  Contra Costa County Connection                       132              0
  SamTrans                                             200            100
  Golden Gate Transit                                   37              0
  Vallejo Transit                                       32              0
  Livermore Amador Valley Transit                       32              0
  WestCAT                                               12              0
  Santa Rosa City Bus                                   25              0
  Santa Clara VTA                                      134             99
  Vacaville City Coach                                   7              0
  Fairfield/Suisun Transit                              25              0
  Tri-Delta Transit                                     49              0
  TOTAL                                               1384            340

MTC (www.mtc.ca.gov) is the transportation planning, financing and coordinating agency for the nine-county San Francisco Bay Area. The Bay Area Quality Management District (www.baaqmd.gov) is the regional agency chartered with protecting air quality in the Bay Area. Cleaire Advanced Emission Controls (www.cleaire.com) designs, manufactures and installs diesel exhaust filters.