Evidence for the role of organics in aerosol particle formation under atmospheric conditions.
New particle formation in the atmosphere is an important parameter in governing the radiative forcing of atmospheric aerosols. However, detailed nucleation mechanisms remain ambiguous, as laboratory data have so far not been successful in explaining atmospheric nucleation. We investigated the formation of new particles in a smog chamber simulating the photochemical formation of H(2)SO(4) and organic condensable species. Nucleation occurs at H(2)SO(4) concentrations similar to those found in the ambient atmosphere during nucleation events. The measured particle formation rates are proportional to the product of the concentrations of H(2)SO(4) and an organic molecule. This suggests that only one H(2)SO(4) molecule and one organic molecule are involved in the rate-limiting step of the observed nucleation process. Parameterizing this process in a global aerosol model results in substantially better agreement with ambient observations compared to control runs.
Metzger
Axel
A
Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
Verheggen
Bart
B
Dommen
Josef
J
Duplissy
Jonathan
J
Prevot
Andre S H
AS
Weingartner
Ernest
E
Riipinen
Ilona
I
Kulmala
Markku
M
Spracklen
Dominick V
DV
Carslaw
Kenneth S
KS
Baltensperger
Urs
U
D000336:Aerosols / Q000737:chemistry; D000393:Air Pollutants / Q000737:chemistry; D001272:Atmosphere / Q000737:chemistry; D002625:Chemistry, Organic / Q000379:methods; D002980:Climate; D004784:Environmental Monitoring / Q000379:methods; D008956:Models, Chemical; D009930:Organic Chemicals / Q000737:chemistry*; D010316:Particle Size; D055668:Photochemical Processes; D012621:Seasons; D012905:Smog; D013464:Sulfuric Acids / Q000737:chemistry
D000336:Aerosols; D000393:Air Pollutants; D009930:Organic Chemicals; D012905:Smog; D013464:Sulfuric Acids; C033158:sulfuric acid