2013 Progress Report: Sensitivity of Organic Aerosol Concentrations and Forcing to Anthropogenic Emissions

EPA Grant Number: R835405
Title: Sensitivity of Organic Aerosol Concentrations and Forcing to Anthropogenic Emissions
Investigators: Pandis, Spyros N. , Donahue, Neil
Institution: Carnegie Mellon University
EPA Project Officer: Peterson, Todd
Project Period: April 1, 2013 through March 31, 2016
Project Period Covered by this Report: April 1, 2013 through March 31,2014
Project Amount: $399,998
RFA: Anthropogenic Influences on Organic Aerosol Formation and Regional Climate Implications (2012) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , Global Climate Change , Climate Change , Air

Objective:

The objectives of the proposed project are: (i) The experimental investigation of the mixing of biogenic and anthropogenic OA components; (ii) the quantification of the effects of NOx on the formation of biogenic SOA; (iii) the measurement of the OA formed per unit of biogenic and anthropogenic SOA precursor added to an air mass; (iv) the development of parameterizations of the above processes in the OA volatility-oxygen content coordinate system (2D-Volatility Basis Set, 2D-VBS); (v) the evaluation of this new module in the regional chemical transport model PMCAMx against some of the best available datasets (SOAS and SENEX-2013 in the US and EUCAARI and PEGASOS in Europe); and (vi) the use of PMCAMx to quantify the response of the biogenic OA and its climatic effects (direct effect and also cloud condensation nuclei concentrations) in the Eastern US for different scenarios of anthropogenic emission changes.
 
The work involves a combination of laboratory measurements, novel field “atmospheric perturbation experiments," OA model development, and modelling in urban and regional scales. The laboratory work will combine a multiple-residence time thermodenuder (TD), including a dilution system with a high-resolution Aerosol Mass Spectrometer, a Scanning Mobility Particle Spectrometer, a Cloud Condensation Nuclei Counter and a Hygroscopic Tandem Differential Mobility Analyzer (all placed after the TD), to investigate the mixing of organic aerosol from anthropogenic and biogenic sources, the effect of NOx on the formation of biogenic SOA. Field work involves perturbation of ambient air inside a chamber and quantification of the change of the OA levels. The results of the laboratory and field perturbation experiments are used for the continued development of parameterizations for the description of the biogenic SOA formation, its interactions with anthropogenic OA, and SO2 in the volatility-oxygen content coordinate system (2D-Volatility Basis Set). The resulting modules will be added to PMCAMx and will be evaluated against the best available datasets.

Progress Summary:

  • The additional SOA formed by the chemical aging of monoterpene and sesquiterpene ozonolysis SOA through reactions with OH results in a modest increase of the original SOA yields (less than 20% in most cases).
  • Very oxidized SOA can be formed during the chemical aging reactions of aromatics (toluene, xylenes) with OH.
  • The continued oxidation of the aromatic SOA is accompanied by a net reduction in volatility. A simple relationship has been derived linking the oxidation state of carbon and the change in effective volatility.
  • Anthropogenic semivolatile SOA components readily mix with biogenic SOA produced during the a-pinene ozonolysis. On the other hand, the opposite process appears to be a lot slower than expected either due to the low volatility of the biogenic SOA or resistances to mass transfer.
  • We have developed a new experimental approach that allows us to investigate chemical and physical processes perturbing ambient air in a laboratory setting. The first experiments allowed us to study new particle formation, growth of these particles by organics, and SOA formation that far exceeds what is expected by the oxidation of the traditional VOC precursors.
  • The simplest parameterization of the 2D-VBS framework using the above results reproduces well the OA observations during the PEGASOS-2012 campaign in Southern Europe.
  • We proposed standardizing a naming convention for organic aerosol classification that is relevant to laboratory studies, ambient observations, atmospheric models, and, quite importantly, the public and their leadership. This framework classifies organic material as primary or secondary pollutants and distinguishes among fundamental features important for science and policy questions including emission source, chemical phase and volatility.
  • Organic aerosol exists throughout the troposphere because heterogeneous oxidation by OH radicals is more than an order of magnitude slower than comparable gas-phase oxidation.

 

Future Activities:

During the second year of the project we will:

  • Perform additional experiments producing the biogenic SOA under high NOx conditions. Our hypothesis is that the first-generation SOA yidelds will be lower, but the chemical aging will increase the SOA significantly.
  • Perform anthropogenic SOA aging experiments.
  • Perform additional ambient aging experiments with better characterization of the VOCs and IVOCs in the system.
  • Continue the development of parameterizations of OA for CTMs.
  • Use PMCAMx and PMCAMx-Trj to simulate the SOAS/SENEX campaign.


Journal Articles on this Report : 5 Displayed | Download in RIS Format

Other project views: All 9 publications 9 publications in selected types All 9 journal articles
Type Citation Project Document Sources
Journal Article Donahue NM, Chuang W, Epstein SA, Kroll JH, Worsnop DR, Robinson AL, Adams PJ, Pandis SN. Why do organic aerosols exist? Understanding aerosol lifetimes using the two-dimensional volatility basis set. Environmental Chemistry 2013;10(3):151-157. R835405 (2013)
R835405 (2014)
R835405 (Final)
  • Full-text: CSIRO Publishing-Full Text-HTML
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  • Abstract: CSIRO Publishing-Abstract
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  • Other: CSIRO Publishing-Full Text-PDF
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  • Journal Article Hildebrandt Ruiz L, Paciga AL, Cerully KM, Nenes A, Donahue NM, Pandis SN. Formation and aging of secondary organic aerosol from toluene:changes in chemical composition, volatility, and hygroscopicity. Atmospheric Chemistry and Physics 2015;15(14):8301-8313. R835405 (2013)
    R835405 (2014)
    R835405 (Final)
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  • Abstract: ACP-Abstract
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  • Other: ResearchGate-Abstract & Full Text-PDF
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  • Journal Article Murphy BN, Donahue NM, Robinson AL, Pandis SN. A naming convention for atmospheric organic aerosol. Atmospheric Chemistry and Physics 2014;14(11):5825-5839. R835405 (2013)
    R835405 (2014)
    R835405 (Final)
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  • Abstract: ACP-Abstract
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  • Other: ResearchGate-Abstract & Full Text-PDF
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  • Journal Article Robinson ES, Saleh R, Donahue NM. Probing the evaporation dynamics of mixed SOA/squalane particles using size-resolved composition and single-particle measurements. Environmental Science & Technology 2015;49(16):9724-9732. R835405 (2013)
  • Abstract from PubMed
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  • Journal Article Tasoglou A, Pandis SN. Formation and chemical aging of secondary organic aerosol during the β-caryophyllene oxidation. Atmospheric Chemistry and Physics 2015;15(11):6035-6046. R835405 (2013)
    R835405 (2014)
    R835405 (Final)
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  • Abstract: ACP-Abstract
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  • Other: ResearchGate-Abstract & Full Text-PDF
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  • Supplemental Keywords:

    air quality modeling, smog, PM, anthropogenic organic aerosol, biogenic organic aerosol

    Progress and Final Reports:

    Original Abstract
    2014 Progress Report
    Final Report