The BART strike has naturally put more vehicles on the road, and with them more air pollution.
Normal traffic — which is consistently rated among the nation's worst — already accounts for 50 percent of the region's air pollution, according to the Bay Area Air Quality Management District. On a typical day, roads carry 3 million to 4 million drivers, said air district spokesman Ralph Borrmann. And the strike has added to that number, he said, since BART averages 400,000 daily riders.
If the average driver was delayed an hour during both the morning and evening commutes — and many were, with the approach to the Bay Bridge in downtown San Francisco on Monday and Tuesday afternoons experiencing delays similar to the worst of getaway Fridays — that's an additional 16 million pounds of carbon emissions and 800,000 gallons of gasoline used, according to the Bay Area Council, which represents some of the region's biggest corporate employers.
However, no Spare the Air alerts have been in effect this week. The air district triggers those when hot, windless weather traps particulate matter, which is then "cooked" to brown smog, Borrmann said.
Bay Area drivers this week have been encouraged by transit officials to carpool or telecommute. Ferry ridership also tripled as the Bay Area sought alternatives to BART and the highways.
And BART is not entirely green itself. The all-electric transit agency gleans one-third of its power from nonrenewable sources, said BART spokeswoman Alicia Trost.