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Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/acp-2017-942
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 4.0 License.
Research article
20 Oct 2017
Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Atmospheric Chemistry and Physics (ACP).
Gas phase composition and secondary organic aerosol formation from gasoline direct injection vehicles investigated in batch and flow reactors: effects of prototype gasoline particle filters
Simone M. Pieber1, Nivedita K. Kumar1, Felix Klein1, Pierre Comte2, Deepika Bhattu1, Josef Dommen1, Emily A. Bruns1, Dogushan Kilic1, Imad El Haddad1, Alejandro Keller3, Jan Czerwinski2, Norbert Heeb4, Urs Baltensperger1, Jay G. Slowik1, and André S.H. Prévôt1 1Paul Scherrer Institute, Laboratory of Atmosp heric Chemistry, CH- 5232 Villigen, Switzerland
2Bern University of Applied Sciences, CH-2560 Nidau, Switzerland
3University of Applied Sciences Northwestern Switzerland; CH-5210 Windisch, Switzerland
4Empa Material Science and Technology; CH-8600 Dübendorf, Switzerland
Abstract. Gasoline direct injection (GDI) vehicles have recently been identified as a significant source of carbonaceous aerosol, of both primary and secondary origin. Here we investigated primary emissions and secondary organic aerosol (SOA) formation from GDI vehicle exhaust for multiple vehicles and driving test cycles, and novel GDI after-treatment systems. Emissions were characterized by proton transfer reaction time-of-flight mass spectrometry (gaseous non-methane organic compounds, NMOCs), aerosol mass spectrometry (sub-micron non-refractory particles), and light attenuation measurements (equivalent black carbon (eBC) determination using Aethalometer measurements) together with supporting instrumentation. We evaluated the effect of retrofitted prototype gasoline particle filters (GPFs) on primary eBC, organic aerosol (OA), NMOCs, as well as SOA formation. Two regulatory driving test cycles were investigated, and the importance of distinct phases within these cycles (e.g. cold engine start, hot engine start, high speed driving) to primary emissions and secondary products was evaluated. Atmospheric processing was simulated using both the PSI mobile smog chamber (SC) and the potential aerosol mass oxidation flow reactor (OFR). GPF retrofitting was found to greatly decrease primary particulate matter (PM) through removal of eBC, but showed limited partial removal of the minor POA fraction, and had no detectable effect on either NMOC emissions (absolute emission factors or relative composition) or SOA production. In all tests, overall primary and secondary PM and NMOC emissions were dominated by the engine cold start, i.e. before thermal activation of the catalytic after-treatment system. Differences were found in the bulk compositional properties of SOA produced by the OFR and the SC (O : C and H : C ratios), while the SOA yields agree within our uncertainties, with a tendency for lower SOA yields in SC experiments. A few aromatic compounds are found to dominate the NMOC emissions (primarily benzene, toluene, xylene isomers and C3-benzenes). A large fraction (> 0.5) of the SOA production was explained by those compounds, based on investigation of reacted NMOC mass and comparison with SOA yield curves of toluene, o-xylene and 1,2,4-trimethylbenzene determined in our OFR within this study. Remaining differences in the obtained SOA yields may result from diverse reasons including aging conditions, unaccounted-for precursors and differences in SOA yields of aromatic hydrocarbons with different degrees of substitution, as well as experimental uncertainties in the assessment of particle and vapor wall losses.

Citation: Pieber, S. M., Kumar, N. K., Klein, F., Comte, P., Bhattu, D., Dommen, J., Bruns, E. A., Kilic, D., El Haddad, I., Keller, A., Czerwinski, J., Heeb, N., Baltensperger, U., Slowik, J. G., and Prévôt, A. S. H.: Gas phase composition and secondary organic aerosol formation from gasoline direct injection vehicles investigated in batch and flow reactors: effects of prototype gasoline particle filters, Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acp-2017-942, in review, 2017.
Simone M. Pieber et al.
Simone M. Pieber et al.
Simone M. Pieber et al.

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Short summary
We study primary emissions and secondary organic aerosol (SOA) from gasoline direct injection (GDI) vehicles retrofitted with novel after-treatment systems (gasoline particle filters, GPF), and we compare SOA formed in a smog chamber to that from an oxidation flow reactor. GPF retrofitting decreases primary particulate matter through removal of refractory black carbon. Non-refractory organic particulates and gases are not significantly altered, and consequently, no SOA reduction is observed.
We study primary emissions and secondary organic aerosol (SOA) from gasoline direct injection...
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