MARYSVILLE — Some Nevada County residents are concerned a casino proposal by the Enterprise Rancheria tribe in Yuba County would worsen air quality at higher elevations.

The tribe is planning to build in an area on Forty Mile Road near Highway 65, south of Marysville toward Wheatland.

Perhaps most prominent of the comments made on the environmental impact statement came from the Sierra Club, whose Sierra Nevada group/Mother Lode chapter is based in Nevada City. In a letter, group conservation chairwoman Barbara Rivenes said the EIS didn't consider the potential for worsened air quality in Nevada County from the casino.

“Western Nevada County is in a ‘non-attainment' area for ozone, which is created and transported from the northern Sacramento Valley and beyond. The negative health effects from ozone are well known and documented,” Rivenes' stated.

Her letter also mentioned comments from Grass Valley Neighbors, a land-use and environmental group. In a separate letter, Steve Enos, who describes himself as a land-use planner with the group, voiced similar concerns about air quality.

“The proposed Enterprise casino in Yuba County would be a large ‘out of area' traffic generator that has the potential to decrease air quality here in Grass Valley,” Enos' letter stated.

“As a result, the proposed casino project ... must undertake a comprehensive and meaningful environmental review to identify potential impacts and possible mitigation measures to address impacts and safeguard the health of the public before a decision is made,” Enos wrote.

Charles Altekruse, a spokesman for the Enterprise Rancheria tribe, said he wasn't aware of the Sierra Club's comments and couldn't directly respond.

“I would say there's a distinct advantage from an environmental standpoint in putting the casino on the valley floor rather than the more ecologically diverse foothills,” he said.

A final record of decision by the federal Bureau of Indian Affairs on whether to allow Estom Yumeka Maidu to take 40 acres into trust for the casino is expected by the end of the year.