A Brookings Institute study released May 29, 2008, titled Shrinking the Carbon Footprint of Metropolitan America, found that U.S. city dwellers have lower carbon footprints than the average American.
The study quantified transportation and residential carbon emissions for the 100 largest U.S. metropolitan areas. Each resident of the largest 100 largest metropolitans areas is responsible on average for 2.47 tons ofin each year, 14 percent below the 2.87 ton U.S. average. Residential density, availability of public transit, carbon intensity of electricity generation, electricity prices, and weather were all important factors in understanding carbon footprints. The study also found that carbon footprints varied widely between cities geographically- carbon emissions are highest in the eastern U.S. where coal is the common source for electricity, and lower in the West where weather is milder and electricity and motor fuel prices have been higher.