Impact of underestimating the effects of cold temperature on motor vehicle start emissions of air toxics in the United States.
Analyses of U.S. Environmental Protection Agency (EPA) certification data, California Air Resources Board surveillance testing data, and EPA research testing data indicated that EPA's MOBILE6.2 emission factor model substantially underestimates emissions of gaseous air toxics occurring during vehicle starts at cold temperatures for light-duty vehicles and trucks meeting EPA Tier 1 and later standards. An unofficial version of the MOBILE6.2 model was created to account for these underestimates. When this unofficial version of the model was used to project emissions into the future, emissions increased by almost 100% by calendar year 2030, and estimated modeled ambient air toxics concentrations increased by 6-84%, depending on the pollutant. To address these elevated emissions, EPA recently finalized standards requiring reductions of emissions when engines start at cold temperatures.
Cook
Richard
R
U.S. Environmental Protection Agency, Office of Transportation and Air Quality, National Vehicle and Fuel Emissions Laboratory, Ann Arbor, MI 48103, USA. cook.rich@epa.gov
Touma
Jawad S
JS
Fernandez
Antonio
A
Brzezinski
David
D
Bailey
Chad
C
Scarbro
Carl
C
Thurman
James
J
Strum
Madeleine
M
Ensley
Darrell
D
Baldauf
Richard
R
D000393:Air Pollutants / Q000032:analysis* / Q000737:chemistry; D000397:Air Pollution / Q000032:analysis*; D003080:Cold Temperature; D004784:Environmental Monitoring; D005742:Gasoline; D018986:Motor Vehicles; D014481:United States; D001335:Vehicle Emissions / Q000032:analysis*
D000393:Air Pollutants; D005742:Gasoline; D001335:Vehicle Emissions