"A recent study by MIT found that the pollution caused by driving causes more early deaths in the United States than the number of people who die each year in traffic crashes. Major sources of combustion pollution are roads and power generation."

Biking in Baltimore
"A recent study by MIT found that the pollution caused by driving causes more early deaths in the United States than the number of people who die each year in traffic crashes. Major sources of combustion pollution are roads and power generation."