Every year Nevada County gets a failing ozone grade from the American Lung Association. This grade is based on figures reported to the Environmental Protection Agency, which gave Nevada County an “F” for ozone pollution again for 2010.
The vast majority of Western Nevada County's ozone air pollution is transported from the Sacramento region and, to a lesser extent, the San Francisco Bay Area, according to a press release from the Northern Sierra Air Quality Management District.
But there is really a larger issue, which was examined at length by the Sierra Environmental Studies Foundation. Here is a link to the Foothill Furor – Seeking Basis for Public Policy on Ozone Pollution
From the Abstract:
“Most people know that the county can do little to impact its ability to reach the federally mandated standards. So far the county’s only countering argument has been that its ozone is transported from large upwind sources. The report introduces two new and significant factors to this issue. These are 1) the government’s assessment of non-attainment is based on an arbitrary interpretation of unknown county ozone levels, and 2) the government has no reasonable (science supported) process in place by which it can either prescribe or evaluate any county attainment plan submitted to it – i.e. it cannot follow its own procedures.”
Emphasis was added by author. Read the whole report, there is no valid science that supports the above grade. Just like global warming, we are being baffled by government cow pies.