The "Tune In and Tune Up" program comes to the fairgrounds in Stockton tomorrow. You can have your car smog tested free of charge.

Anthony Presto with the San Joaquin Valley Air District says the program is designed to get gross polluters off the road. He says one of every two cars tested is expected to fail.

PRESTO:  "And if it fails, they will be issued a voucher and have repairs done, up to $500 so that the vehicle will pass their smog check."

The Air District funds the program with DMV fees, and Presto says repeated surveys indicate San Joaquin Valley's bad air is second only to Los Angeles.

PRESTO:  There's a lot of negative effects and the biggest negative effect is the public health, so we're trying to do everything we can to protect public health by having programs like this."

The program is only for people who live in the San Joaquin Valley, which stretches from San Joaquin to Kern County.