CaltechAUTHORS
  A Caltech Library Service

Modeling the Formation of Secondary Organic Aerosol. 1. Application of Theoretical Principles to Measurements Obtained in the α-Pinene/, β-Pinene/, Sabinene/, Δ^3-Carene/, and Cyclohexene/Ozone Systems

Pankow, James F. and Seinfeld, John H. and Asher, William E. and Erdakos, Garnet B. (2001) Modeling the Formation of Secondary Organic Aerosol. 1. Application of Theoretical Principles to Measurements Obtained in the α-Pinene/, β-Pinene/, Sabinene/, Δ^3-Carene/, and Cyclohexene/Ozone Systems. Environmental Science and Technology, 35 (6). pp. 1164-1172. ISSN 0013-936X. https://resolver.caltech.edu/CaltechAUTHORS:20170316-090119069

[img] PDF - Supplemental Material
See Usage Policy.

273Kb

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20170316-090119069

Abstract

Secondary organic aerosol (SOA) forms in the atmosphere when volatile parent compounds are oxidized to form low-volatility products that condense to yield organic particulate matter (PM). Under conditions of intense photochemical smog, from 40 to 80% of the particulate organic carbon can be secondary in origin. Because describing multicomponent condensation requires a compound-by-compound identification and quantification of the condensable compounds, the complexity of ambient SOA has made it difficult to test the ability of existing gas/particle (G/P) partitioning theory to predict SOA formation in urban air. This paper examines that ability using G/P data from past laboratory chamber experiments carried out with five parent hydrocarbons (HCs) (four monoterpenes at 308 K and cyclohexene at 298 K) in which significant fractions (61−100%) of the total mass of SOA formed from those HCs were identified and quantified by compound. The model calculations were based on a matrix representation of the multicomponent, SOA G/P distribution process. The governing equations were solved by an iterative method. Input data for the model included (i) ΔHC (μg m^(-3)), the amount of reacted parent hydrocarbon; (ii) the α values that give the total concentration T (gas + particle phase, ng m^(-3)) values for each product i according to Ti = 10^3 αiΔHC; (iii) estimates of the pure compound liquid vapor pressure P^o_L values (at the reaction temperature) for the products; and (iv) UNIFAC parameters for estimating activity coefficients in the SOA phase for the products as a function of SOA composition. The model predicts the total amount M_o (μg m^(-3)) of organic aerosol that will form from the reaction of ΔHC, the total aerosol yield Y (= M_o/ΔHC), and the compound-by-compound yield values Y_i. An impediment in applying the model is the lack of literature data on P^o_L values for the compounds of interest or even on P^o_L values for other, similarly low-volatility compounds. This was overcome in part by using the G/P data from the α-pinene and cyclohexene experiments to determine P^o_L values for use (along with a set of 14 other independent polar compounds) in calculating UNIFAC vapor pressure parameters that were, in turn, used to estimate all of the needed P^o_L values. The significant degree of resultant circularity in the calculations for α-pinene and cyclohexene helped lead to the good agreement that was found between the Y_i values predicted by the model, and those measured experimentally for those two compounds. However, the model was also able to predict the aerosol yield values from β-pinene, sabinene, and Δ^3-carene, for which there was significatly less circularity in the calculations, thereby providing evidence supporting the idea that given the correct input information, SOA formation can in fact be accurately modeled as a multicomponent condensation process.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/es001321dDOIArticle
http://pubs.acs.org/doi/abs/10.1021/es001321dPublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/es001321dPublisherSupporting Information
ORCID:
AuthorORCID
Seinfeld, John H.0000-0003-1344-4068
Additional Information:© 2001 American Chemical Society. Received 2 June 2000. Date accepted 12 December 2000. Published online 14 February 2001. Published in print 1 March 2001. This work was supported by U.S. Environmental Protection Agency Grant R826371-01-0.
Funders:
Funding AgencyGrant Number
Environmental Protection Agency (EPA)R826371-01-0
Issue or Number:6
Record Number:CaltechAUTHORS:20170316-090119069
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170316-090119069
Official Citation:Modeling the Formation of Secondary Organic Aerosol. 1. Application of Theoretical Principles to Measurements Obtained in the α-Pinene/, β-Pinene/, Sabinene/, Δ3-Carene/, and Cyclohexene/Ozone Systems James F. Pankow, John H. Seinfeld, William E. Asher, and Garnet B. Erdakos Environmental Science & Technology 2001 35 (6), 1164-1172 DOI: 10.1021/es001321d
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:75177
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:16 Mar 2017 17:22
Last Modified:03 Oct 2019 16:47

Repository Staff Only: item control page