Rush hour traffic in Seattle, Wash.

If you consider yourself a green driver, you should know your car's air pollution score.

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A few years ago, air pollution ratings and fuel efficiency were among the last things car buyers considered before making a purchase. After all, the atmosphere covers the entire globe -- what difference was one little full-size SUV going to make? Today, attitudes have changed in a major way. It's now cool to be green, and your vehicle is one of the most visible markers of your concern for the environment. Of all the things you can buy, a vehicle can make the biggest impact on your carbon footprint.

This shift in perception and the growing popularity of eco-friendly driving has many people wondering about their cars' air pollution score. Knowing this score provides you with a quick measure of where you and your car stand on the scale of green driving. Simply stated, the lower your vehicle's air pollution score, the dirtier it is. The higher the score, the closer you and your vehicle are to the ideal of low-impact, eco-friendly driving.

In addition to your air pollution score, you'll probably want to know about your vehicle's fuel consumption for a number of reasons. Greater fuel efficiency means you'll have to pay less at the pump than you would if you drove a more fuel-thirsty car or truck. It also means that you'll be releasing fewer toxic pollutants and greenhouse gases into the atmosphere as you drive.

To find out how to get your vehicle's air pollution score, go to the next page.