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Contribution of secondary condensable organics to new particle formation: A case study in Houston, Texas
Author(s) -
Fan Jiwen,
Zhang Renyi,
Collins Don,
Li Guohui
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl026295
Subject(s) - nucleation , aerosol , particle number , particle (ecology) , ultrafine particle , environmental science , cmaq , atmospheric sciences , particle size , meteorology , air quality index , materials science , chemistry , chemical physics , thermodynamics , physics , geology , nanotechnology , oceanography , volume (thermodynamics)
We report aerosol simulations using the EPA's Models‐3 Community Multiscale Air Quality model (CMAQ) and ground‐based and aircraft aerosol measurements to investigate new particle formation in Houston, Texas. The aerosol measurements reveal elevated ultrafine particles that reach the highest value in the afternoon, indicating prominent new particle formation. Simulations of the binary H 2 SO 4 ‐H 2 O nucleation predict an order of magnitude lower concentrations for aerosols near 10 nm than the measurements. A parameterized nucleation scheme that accounts for the enhanced nucleation effect of secondary condensable organics is incorporated into the Models‐3/CMAQ. The organic nucleation scheme predicts the number concentrations in agreement with the measurements during the daytime. The diurnal variation is well reproduced in the simulations including the organic nucleation scheme. Comparison with the aircraft measurements also shows that the organic nucleation scheme produces good predictions of the altitude‐dependent number size distributions of the ultrafine particles. The results corroborate the importance of secondary condensable organics in new particle formation when sulfate and organics are abundant.