I wasn't surprised when the EPA rejected California's request for a waiver so that it could set more stringent rules limiting CO2 emissions from vehicles than the federal government requires. That's because tying the argument to global warming is scientifically hard to prove and because of the way greenhouse gases mix in the atmosphere it is more of a global than local problem.

However, just when California needed a study to emphasize the local effects of CO2 on human health for its lawsuit against the EPA, a Stanford researcher provides that exact ammunition. The study confirms that rising CO2 levels increases human mortality because it exacerbates the problem of ozone and other air pollutants.

This is the argument that California needs to make: people in the state are becoming ill and dying because of CO2, and autos are a major contributor to that problem. To be fair however, California should also be looking at concrete production as a contributor to the CO2 problem.

CO2 is also injurious to those with asthma, emphysema and other < a href="http://www.respiratoryreviews.com/jun04/rr_jun04_breathing.html">respiratory problems, which should be high up on the California complaint as well.

Hopefully the next administration will make the changes that California and 15 other states are asking for so that we don't have to spend more taxpayer dollars on fights between the states and the federal government.