 Mobile SourcesMobile sources of air pollution are simply that: things that pollute as they move from one place to another. They're called mobile sources, because the pollution doesn't start or end up in one place - it's scattered. And that's the biggest problem, really - because the pollution moves around, it's harder to control or limit or clean up than pollution that stays in one place. Mobile sources include cars, trucks, SUVs, boats, trains, planes, buses - anything that moves and produces air pollution. In many cities, collective personal automobile use (i.e., driving!) is the greatest source of pollution. Though many pollution control devices have been installed in autos, more people are driving on the roads and traveling longer distances. Americans drive over 2.3 billion miles a year, an average of 11,400 miles in each passenger vehicle! (Nucleus Vol. 21 No. 2 Summer 1999 p. 3). With the increasing popularity of large trucks and SUVs (sport utility vehicles) for travel, more and more gas is being used to travel a shorter distance. Combining these circumstances, it is not surprising that fuel use is on the rise. According to the EPA, driving an automobile is probably a person's most "polluting" daily activity. The main pollutants emitted from vehicles are carbon monoxide, nitrogen oxide, reactive hydrocarbons, and particulates. These can react with other compounds, creating smog, acid rain, and global climate change. Vehicles spew pollutants in two ways: through the tailpipe after the combustion process, or directly by evaporation. Also read about evaporative emissions> |
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