ABSTRACT

        An emerging issue in air pollution today is how to improve local
air quality and address global warming simultaneously. Particulate black
carbon (BC), the main component of soot, is a pollutant that is well known
to degrade air quality and impair human health. Soot also absorbs solar
radiation, heating the air and reducing sunlight reaching the ground. As
diesel soot leaves the tailpipe of a vehicle, it internally-mixes with
other particle components by coagulation and growth. The internal mixing of
soot with other chemicals enhances the solar absorption of BC, a phenomenon
that has now been proven experimentally. Because of this phenomenon, BC
from fossil fuels and biomass burning may be the second-leading cause of
global warming after carbon dioxide and ahead of methane in terms of direct
forcing. Because of its short lifetime and the relative strength of its 
warming effect, controlling BC might be the most effective method, in terms
of its speed, of slowing global temperature rise for a specific period.
Because CO2 causes most global warming and its effects last longer, though,
it should be controlled immediately as well. The addition of particle traps
to existing diesel vehicles is one method of reducing the climate effect of
BC. However, the potential use of modern diesel vehicles, which contain
particle traps and NOx filters, in place of new gasoline vehicles, which is
being encouraged in the in the U.S. under the proposed energy bill and
European Union, may enhance photochemical smog over the U.S. due to several
factors. In this talk, the evolution of aerosol particles near a freeway,
the effect of modern diesel versus gasoline vehicles on photochemical smog
throughout the U.S., and the global-scale effect of particulate 
black carbon on climate will be discussed.   






Go to current seminar listing


Back to home page