Rebecca Plevin / Valley Public Radio

Anna Martinez was standing on a street corner in the tiny farmworker community of Kettleman City when she heard the familiar sound of a truck engine roaring to life.

She pointed to a diesel truck parked on a lot next to three others. The lot was just one block from State Route 41, and another block or so from a huge agricultural field.

“We’ll see how long he’s going to idle,” said Martinez, a community organizer with Greenaction for Health and Environmental Justice. “He’s just now starting his truck - see all the emissions and black smoke.”