The Central Valley already has some of the dirtiest air in the country according to the E-P-A.
State regulators and environmental organizations say the Bush administration's proposal would halt the monitoring of dust in rural areas as well as exempting farms and mines from some existing air pollution standards.
Jamie Holt of San Joaquin Valley Air Pollution Control District says the plan would create a double-standard.
"On the face of it, it looks like urban areas will be treated different than rural areas and we don't feel there should be two public health standards depending on where you live."
One environmental group says granting farms and mines exemptions raises constitutional questions.
But some farmers and miners are pleased with the proposal, claiming they have long been blamed for more air pollution than they actually cause.