Turn Your SUV Into A Zero-Emissions Vehicle

"For $160 you can turn a Hummer H2 into a zero-emissions vehicle. No tools or mechanical ability are required...The idea is the latest implementation in the trading of "pollution credits." Those are the market-based innovations, introduced a few years ago, which allow smoke-spewing companies to buy and sell the right to emit certain amounts of pollutants into the air...That way, you can drive your car while having no net effect on the amount of pollution in the air, the company says."