HR: 09:45h
AN: A51E-07 [Abstracts]
TI: Global Budgets of Atmospheric Glyoxal and Methylglyoxal, and Implications for Formation of Secondary Organic Aerosols
AU: * Fu, T
EM: fu@fas.harvard.edu
AF: Department of Earth and Planetary Sciences, Harvard University, 29 Oxford Street,
Cambridge, MA 02138, United States
AU: Jacob, D J
EM: djacob@fas.harvard.edu
AF: Department of Earth and Planetary Sciences, Harvard University, 29 Oxford Street,
Cambridge, MA 02138, United States
AB:
We present the first global budgets of atmospheric glyoxal and methylglyoxal with the goal of quantifying their
potential for global secondary organic aerosol (SOA) formation via irreversible uptake by aqueous aerosols and
clouds. Our explicit simulation of glyoxal and methylglyoxal is based on the best current knowledge of source and
sink processes. Global sources of glyoxal and methylglyoxal are 45 Tg y-1 and 140 Tg y-1, respectively.
Isoprene is the largest global source of both dicarbonyls, producing 45% of glyoxal and 85% methylglyoxal.
Acetylene and acetone act as background dicarbonyl sources due to their long lifetime. Atmospheric lifetimes of
glyoxal and methylglyoxal are 2.9 hours and 1.6 hours, respectively, mainly due to removal by photolysis. Our
simulated dicarbonyl concentrations at northern mid-latitudes during the growing season are in the range 10-100
ppt, consistent with in situ measurements. On a global scale, the highest simulated dicarbonyl concentrations
are over biomass burning regions, in agreement with satellite observations. The global source of SOA from the
irreversible uptake of dicarbonyls is estimated to be 11 Tg C y-1, including 2.6 Tg C y-1 from glyoxal and
8 Tg C y-1 from methylglyoxal. The dicarbonyl pathway could make a large contribution to SOA in the free
troposphere over source regions, particularly under low-NOx conditions.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting