Thursday may be the first Spare the Air Day of the season, but there will be no free public transit rides that day even if smog reaches unhealthy levels — unlike past years.

Changing course in its battle against air pollution, the region's clean air agency has decided to hold just one day of free rides this year and to announce it weeks in advance.

The free ride day is tentatively scheduled for June 19, subject to final approval later this month by the Metropolitan Transportation Commission. Rides will be free all day on buses, and until mid-day on BART, trains and ferries.

The region had two free fare days in 2007 and six days in 2006.

Pollution and transit officials say the grant money for free ride days is drying up, and those funds could be spent more effectively if diverted to other activities that promote pollution reduction year round, not just on smoggy days. One idea is to finance coupons for school children to ride public transit buses to school.

"We want to spare the earth every day," said Mark Ross, a Martinez city councilman who serves on the Bay Area Air Quality Management District board. "We want to reduce emissions of global warming gases throughout the year."

It costs about $2 million a day to offer free transit rides. Critics complained about the air district and the Metropolitan Transportation Commission spending that much money to reimburse transit agencies for fares.

Copyright 2008 San Jose Mercury News