Fresno truck business owner Jim Ganduglia told me the proposed state air rule on diesel trucks will run him out of business by 2013. Environmentalists doubt him.

This may sound like the usual argument, but you need to understand that there is no truck rule like this anywhere in the world.

Nobody orders pollution cutbacks on trucking fleets that are already on the road. The traditional approach is to require better engines and cleaner fuels -- before folks buy them.

Ganduglia says he'll need to replace seven of his 27 trucks at a cost close to $1 million in five years. He says the process is happening too quickly. It needs to slow down, or the public will need to help the industry.

Environmentalists say truckers are simply doing what businesses always do when ground-breaking regulation comes: Over-estimate the cost and claim they are going out of business.

It's not front-page news, but it is a crucial argument. Diesel trucks are the single biggest air quality problem confronting the San Joaquin Valley.

The soot and chemicals in the exhaust must be controlled if this region has any hope of healthy air in the next decade. And the trucking industry is a linchpin in the state's economy.

Another workshop will be held in Fresno from 10 a.m. to 2 p.m. Aug. 5 at the Fresno County Plaza Ballroom, 2220 Tulare St. The California Air Resources Board will vote on this precedent-setting rule in October.