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CalNex-LA

Duration: 2010-2012

Contact: André Prévôt, andre.prevot@psi.ch

Scope of project

Los Angeles is still famous for its photochemical smog although the pollution levels have decreased a lot since the 70s. Within the CalNex campaign, PSI contributes to the assessment of the sources of particulate matter. A HiVol sampler was run at 3-4 hours time resolution with subsequent 14C analyses to assess the contribution of fossil and non-fossil carbon to the aerosols in Pasadena. The samples of the rotating drum impactor (2-hourly resolution) are further analyzed with synchrotron x-ray fluoresence analyzing the elemental composition of elements larger than magnesium. In a new setup, we also plan to measure sodium on these samples.

Field campaign

Dates	15 May - 16 June 2010
Location	Campus of the California Institute of Technology (Caltech), Pasadena, California
Instruments (PSI)	1 RDI (Rotating Drum Impactor), 1 HiVol Sampler

Field campaign

A diurnal cycle of fossil and non-fossil OC and TC was determined. Non-fossil fractions were found to be 58%± 15% and 51%± 15% for OC and TC, respectively.

Non-fossil carbon concentrations in Pasadena are constant throughout the day whereas a fossil afternoon increase after arrival of the western Los Angeles basin plume is evident.

This fossil increase is mainly due to fresh SOA formed in the LA basin plume.

SOC formation from gasoline emissions most likely dominates over diesel in the LA basin.

Publications

Journal Articles

Light-absorbing soluble organic aerosol in Los Angeles and Atlanta: A contrast in secondary organic aerosol.
Zhang, X., Y.-H. Lin, J. D. Surratt, P. Zotter, A. S. H. Prévôt, and R. J. Weber, 2011
Geophys. Res. Lett., 38, L21810.

Gasoline emissions dominate over diesel in formation of secondary organic aerosol mass.
Bahreini, R., A. M. Middlebrook, J. A. de Gouw, C. Warneke, M. Trainer, C. A. Brock, H. Stark, S. S. Brown, W. P. Dube, J. B. Gilman, K. Hall, J. S. Holloway, W. C. Kuster, A. E. Perring, A. S. H. Prevot, J. P. Schwarz, J. R. Spackman, S. Szidat, N. L. Wagner, R. J. Weber, P. Zotter, and D. D. Parrish, 2012
Geophys. Res. Lett., 39, L06805.
DOI: 10.1029/2011GL050718

Diurnal cycle of fossil and non-fossil carbon using radiocarbon analyses during CalNex.
Zotter, P., I. El-Haddad, Y. Zhang, P. L. Hayes, X. Zhang, Y.-H. Lin, L. Wacker, J. Schnelle-Kreis, G. Abbaszade, R. Zimmermann, J. D. Surratt, R. Weber, J. L. Jimenez, S. Szidat, U. Baltensperger, and A. S. H. Prévôt, 2014
Journal of Geophysical Research: Atmospheres, *2013JD021114.
DOI: 10.1002/2013JD021114

Modeling the formation and aging of secondary organic aerosols in Los Angeles during CalNex 2010.
Hayes, P. L., A. G. Carlton, K. R. Baker, R. Ahmadov, R. A. Washenfelder, S. Alvarez, B. Rappenglück, J. B. Gilman, W. C. Kuster, J. A. de Gouw, P. Zotter, A. S. H. Prévôt, S. Szidat, T. E. Kleindienst, J. H. Offenberg, P. K. Ma, and J. L. Jimenez, 2015
Atmos. Chem. Phys., 15, 5773-5801.
DOI: 10.5194/acp-15-5773-2015

Conference Contributions

High time-resolution elemental composition of particulate matter in Pasadena.
Visser, S., M. Furger, and A.S.H. Prévôt, 2011.
CalNex Data Analysis Workshop, Sacramento, California, USA, 16-19 May 2011.

Diurnal cycle of fossil and non-fossil total carbon using 14C analyses during CalNex
Zotter, P., Prévôt, A. S. H., Zhang, Y. L., Szidat, S., Zhang, X., Lin, Y.-H., Hayes, P., Schnelle-Kreis, J., Seibert, G., Zimmermann, R., Surratt, J. D., Jimenez, J. L., Weber, R. and Baltensperger, U., 2011
CalNex Data Analysis Workshop, Sacramento, California, USA, 16-19 May 2011.

Diurnal cycle of fossil and non-fossil total carbon using 14C analyses during CalNex
Zotter, P., Zhang, Y. L., Hayes, P., Zhang, X., Lin, Y.-H., Szidat, S., Surratt, J. D., Weber, R., Jimenez, J. L., Baltensperger, U. and Prévôt, A. S. H, 2011
European Aerosol Conference, Manchester, UK, 4-9 September 2011