Mary Nichols doesn't explain CARB errors

Mary Nichols, chairwoman of the California Air Resources Board [CARB], has a lot of explaining to do about new-found errors in in the scientific analysis used to toughen California's clean-air standards. The San Francisco Chronicle noted:

Mary Nichols, chairwoman of the California Air Resources Board, offered no explanation when The Chronicle questioned her about the diesel emissions miscalculation. She was recently asked why the air board estimate of a nitrous oxide source was off by at least a factor of two - air board scientists have since revised their numbers, and data show the estimate was off by 340 percent. Nichols' response: "I can't answer that for you."
Nichols was emphatic, though, when asked whether she has concerns about other scientific calculations made by air board scientists.
"No, no, no, no, no, no, no and no," she said.

As noted elsewhere, CARB had hired a scientist (Tran) who falsely claimed a UCal Ph.D., but who in fact had a mail order degree.

**The CARB error comes at a bad time for CARB. Reuters notes:

Next month, California voters will decide on Proposition 23, an oil industry-promoted measure that would effectively repeal the state's pioneering emissions-reduction law, AB32. AB32 is due to take effect next year unless Prop 23 passes, and questions about the science behind California's air and carbon dioxide emissions could provide ammunition to Prop 23's supporters.

See also USAToday California revising air pollution regs after huge miscalculation