View source for Papers:Fu et al 2008

'''Abstract |''' We construct 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. We conduct a detailed simulation of
glyoxal and methylglyoxal in the GEOS-Chem global 3-D chemical transport model
including our best knowledge of source and sink processes. Our resulting best estimates of
the global sources of glyoxal and methylglyoxal are 45 Tg/a and 140 Tg/a,
respectively. Oxidation of biogenic isoprene contributes globally 47% of glyoxal and 79%
of methylglyoxal. The second most important precursors are acetylene (mostly
anthropogenic) for glyoxal and acetone (mostly biogenic) for methylglyoxal. Both
acetylene and acetone have long lifetimes and provide a source of dicarbonyls in the free
troposphere. Atmospheric lifetimes of glyoxal and methylglyoxal in the model are 2.9 h
and 1.6 h, respectively, mostly determined by photolysis. Simulated dicarbonyl
concentrations in continental surface air at northern midlatitudes are in the range
10–100 ppt, consistent with in situ measurements. On a global scale, the highest
concentrations are over biomass burning regions, in agreement with glyoxal column
observations from the SCIAMACHY satellite instrument. SCIAMACHY and a few
ship cruises also suggest a large marine source of dicarbonyls missing from our
model. The global source of SOA from the irreversible uptake of dicarbonyls in
GEOS-Chem is 11 Tg C/a, including 2.6 Tg C/a from glyoxal and 8 Tg C/a
from methylglyoxal; 90% of this source takes place in clouds. The magnitude of the
global SOA source from dicarbonyls is comparable to that computed in GEOS-Chem
from the standard mechanism involving reversible partitioning of semivolatile
products from the oxidation of monoterpenes, sesquiterpenes, isoprene, and aromatics.


'''Publication |''' '''Fu, T.-M.*''', D. J. Jacob, F. Wittrock, J. P. Burrows, M. Vrekoussis, and D. K. Henze (2008), Global budgets of atmospheric glyoxal and methylglyoxal, and implications for formation of secondary organic aerosols, ''J. Geophys. Res.'', 113, D15303, doi:10.1026/2007JD009505. [http://162.105.245.3/~tmfu/web/papers/Fu_et_al_2008.pdf PDF]