Expert: Harold Garabedian - 9/29/2008

Question
how much do gasoline powered passenger automobiles contribute to the total air pollution in the us( in percentage ) ie % of the total carbon footprint?  thanks

Answer
Emissions from gasoline powered vehicles contribute to a host of air pollution concerns including global warming, airborne toxins and general health threatening air pollution (i.e. smog, fine particulate matter, acid rain, etc.).  Regulations are in place which provide emissions standards that auto manufacturers need to certify that their vehicle meet before they can be offered for sale. These standards are for the air contaminants carbon monoxide, hydrocarbons, and nitrogen oxides.

Nationally, Transportation (in general, this would include not only gasoline powered car, but diesel powered trucks and buses and the like) are responsible for some 58% of carbon monoxide emissions, 34% of hydrocarbon emissions and 57% of nitrogen oxides.

Emissions of carbon dioxide (a concern for global warming) result from the combustion of the carbon based fuel. Nationally, the Transportation sector is responsible for about 28% of the US greenhouse gas emissions.

Two web address that can provide more detail on this are:

For general air pollution emissions: http://www.epa.gov/air/oaqps/emissns.html#about

For Greenhouse Gas emissions:
http://www.epa.gov/climatechange/emissions/usinventoryreport.html