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TRANSACTIONS NEWSLETTER ONLINE

September / October 2006

Innovations:

State-of-the-Art Bus Filters Remove Tons of Soot From Bay Area Air

Gavin Newsom
A newly retrofitted diesel bus passes San Francisco Mayor Gavin Newsom’s white-handkerchief test with flying colors, leaving the cloth soot-free. (Photo: Peter Beeler)

Bay Area residents can expect the region’s normally excellent air quality to become even better, as MTC, the Bay Area Air Quality Management District and the area’s transit systems near completion of an unprecedented diesel clean-up program.

The project partners recently held a press conference to highlight their progress and show off some of the buses that have been retrofitted with state-of-the-art diesel exhaust filters. On hand at the Treasure Island event was San Francisco Mayor Gavin Newsom, who conducted a white-handkerchief test on the exhaust pipe of one of the buses. The mayor deposited the still-white handkerchief in his breast pocket, underscoring that the vehicle passed with flying colors.

“We have to step up to the plate,” Newsom said. “We have an obligation to deal with the realities of our emissions — with our fleet of buses and other polluting sources — to turn the tide of global warming.”

San Francisco Muni has already completed the retrofit of all 424 of its targeted buses — the highest number among the involved operators. In all, more than 1,700 diesel buses from 12 Bay Area transit districts are being retrofitted with the diesel exhaust filters. Combined, these high-tech filters annually will capture more than 50 tons of harmful particulate matter and 400 tons of oxides of nitrogen.

Diesel particulate matter is a toxic air contaminant that can cause lung and cardiac disease and increase the risk of cancer. Oxides of nitrogen are a precursor to ozone, which can cause or exacerbate respiratory disease.

MTC covered the bulk of the roughly $30 million cost of the program, primarily with federal funds. Installation of the devices, which are manufactured by San Leandro-based Cleaire Advanced Emission Controls, began in 2003. Nearly 1,400 exhaust filters have been delivered to the involved transit agencies.

While the 12 Bay Area transit districts participating in the bus retrofit have purchased some new, cleaner buses, most of the region’s diesel exhaust reductions are coming from the installation of the 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 oxides of nitrogen created by the buses’ engines. Each installation costs about $20,000, compared to $350,000 or more for a new bus.

“Retrofitting buses is a highly cost-effective way to clean our air,” said MTC Executive Director Steve Heminger.
— John Goodwin

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