Well, CO2 means 1 Carbon molecules and 2 Oxygen molecules. This means the overall for Carbon is a third (1/3). The percentage of this can be best shown as 33.333 reccuring.
An average passenger vehicle produces 5.2 metric tons of Carbon Dioxide per year.
Given 250 million cars in the USA, that equals 1 Billion 300 million (1,300,000,000) Metric Tons per...
In the US alone cars released 314 million metric tons in 2004. The rest of the world is about the same amount all together because they don't drive as far or as much as we do. By those rates its...