Field measurements of secondary organic aerosol (SOA) find higher mass loads than predicted by models, sparking intense efforts to find additional SOA sources but leaving the assumption of rapid SOA evaporation unchallenged. We characterized room-temperature evaporation of pure SOA and SOA formed in the presence of spectator organic vapors with and without aging. We find that it takes ~24 hrs for pure SOA particles to evaporate 75% of their mass, which is in sharp contrast to the ~10 minutes timescales predicted by models. The presence of spectator organic vapors and aging dramatically reduces the evaporation, and in some cases nearly stops it. For all cases, SOA evaporation behavior is size independent and does not follow the liquid droplet evaporation kinetics assumed by models.
Revised: April 23, 2012 |
Published: February 8, 2011
Citation
Vaden T.D., D.g. Imre, J. Beranek, M.B. Shrivastava, and A. Zelenyuk. 2011.Evaporation Kinetics and Phase of Laboratory and Ambient Secondary Organic Aerosol.Proceedings of the National Academy of Sciences of the United States of America 108, no. 6:2190-2195.PNNL-SA-73526.doi:10.1073/pnas.1013391108