ver 1/2 of the air pollution in California comes from driving. Even though today's cars are far cleaner than cars 30 years ago, producing far less pollutants -- 99% less VOCs, 96% less carbon monoxide, and 95% less nitrogen oxide--these gains in reducing air pollution are dwindling because we are driving millions more miles every day. Driving less and driving smart are two big ways to pollute less and save money.