@Jason818: Fuels derived from ancient organic matter, called fossil fuels can cause air pollution when burnt, as anything that burns can. The carbon dioxide created from burning fossil fuels is plant food. I have been researching climate science for 4 years now and have yet to find any evidence that carbon dioxide emissions from anthropological sources, that make up just 3% of total global emissions from all sources, 97% are from natural sources, are not causing any harm to the environment. The global temperatures have not increased in the last 17 years, 3 months, even though emissions have increased 20% during this time.
I'm a computer scientist and a mathematician, I rarely drive a car and have only purchased $10 worth of gas this entire century so far. I ride my bike or walk wherever I go, I don't even use public transport.
Alternatives to fossil fuels have environmental consequences as well.