Characterization of the aerosol over the sub-arctic north east Pacific Ocean

Phinney, L.; Leaitch, W. R.; Lohmann, Ulrike; Boudries, H.; Worsnop, Douglas R.; Jayne, John T.; Toom-Sauntry, D.; Wadleigh, Moire A.; Sharma, Sangeeta; Shantz, N. C.

doi:10.1016/j.dsr2.2006.05.044

Cited by 102 publications

(132 citation statements)

References 49 publications

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“…While the relative magnitude of the major peaks is slightly different in the diesel bus and ship exhaust particulate mass spectra, the major peaks themselves are the same. These are the same major peaks observed by Phinney et al (49) (50). Peaks known to be associated with PAHs were also observed in the C-ToF-AMS mass spectrum at m/z values above 200.…”

Section: Flight Tracks and Meteorologysupporting

confidence: 84%

Comprehensive Simultaneous Shipboard and Airborne Characterization of Exhaust from a Modern Container Ship at Sea

Murphy

Agrawal

Sorooshian

et al. 2009

Environ. Sci. Technol.

197

177

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We report the first joint shipboard and airborne study focused on the chemical composition and water-uptake behavior of particulate ship emissions. The study focuses on emissions from the main propulsion engine of a Post-Panamax class container ship cruising off the central coast of California and burning heavy fuel oil. Shipboard sampling included microorifice uniform deposit impactors (MOUDI) with subsequent offline analysis, whereas airborne measurements involved a number of real-time analyzers to characterize the plume aerosol, aged from a few seconds to over an hour. The mass ratio of particulate organic carbon to sulfate at the base of the ship stack was 0.23 ( 0.03, and increased to 0.30 ( 0.01 in the airborne exhaust plume, with the additional organic mass in the airborne plume being concentrated largely in particles below 100 nm in diameter. The organic to sulfate mass ratio in the exhaust aerosol remained constant during the first hour of plume dilution into the marine boundary layer. The mass spectrum of the organic fraction of the exhaust aerosol strongly resembles that of emissions from other diesel sources and appears to be predominantly hydrocarbon-like organic (HOA) material. Background aerosol which, based on air mass back trajectories, probably consisted of aged ship emissions and marine aerosol, contained a lower organic mass fraction than the fresh plume and had a much more oxidized organic component. A volume-weighted mixing rule is able to accurately predict hygroscopic growth factors in the background aerosol but measured and calculated growth factors do not agree for aerosols in the ship exhaust plume. Calculated CCN concentrations, at supersaturations ranging from 0.1 to 0.33%, agree well with measurements in the ship-exhaust plume. Using sizeresolved chemical composition instead of bulk submicrometer composition has little effect on the predicted CCN concentrations because the cutoff diameter for CCN activation is larger than the diameter where the mass fraction of organic aerosol begins to increase significantly. The particle number emission factor estimated from this study is 1.3 × 10 16 (kg fuel) -1 , with less than 1 / 10 of the particles having diameters above 100 nm; 24% of particles (>10 nm in diameter) activate into cloud droplets at 0.3% supersaturation.

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Section: Flight Tracks and Meteorologysupporting

confidence: 84%

Comprehensive Simultaneous Shipboard and Airborne Characterization of Exhaust from a Modern Container Ship at Sea

Murphy

Agrawal

Sorooshian

et al. 2009

Environ. Sci. Technol.

197

177

View full text Add to dashboard Cite

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“…The collection efficiency of particles by the oven is assumed to be 100% for this dataset. This assumption is based on the comparison of the sulphate mass concentrations from the Q-AMS with those from the ParticleIn-Liquid-Sampler (PILS; described below), and it is consistent with previous results with this Q-AMS (Rupakheti et al, 2005;Buset et al, 2006;Phinney et al, 2006;Langley et al, 2010); more acidic sulphate, as here, is efficiently sampled. Analysis of AMS data was performed using the Deluxe 1.29 IGOR data analysis package (Allan et al, 2003) with a batch file (used for quantitative calibration) and fragmentation file (used for identification of chemical species present on the aerosol) customized to this data set.…”

Section: Instrumentationsupporting

confidence: 71%

Cloud albedo increase from carbonaceous aerosol

et al. 2010

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Abstract. Airborne measurements from two consecutive days, analysed with the aid of an aerosol-adiabatic cloud parcel model, are used to study the effect of carbonaceous aerosol particles on the reflectivity of sunlight by water clouds. The measurements, including aerosol chemistry, aerosol microphysics, cloud microphysics, cloud gust velocities and cloud light extinction, were made below, in and above stratocumulus over the northwest Atlantic Ocean. On the first day, the history of the below-cloud fine particle aerosol was marine and the fine particle sulphate and organic carbon mass concentrations measured at cloud base were 2.4 µg m −3 and 0.9 µg m −3 respectively. On the second day, the below-cloud aerosol was continentally influenced and the fine particle sulphate and organic carbon mass concentrations were 2.3 µg m −3 and 2.6 µg m −3 respectively. Over the range 0.06-0.8 µm diameter, the shapes of the below-cloud size distributions were similar on both days and the number concentrations were approximately a factor of two higher on the second day. The cloud droplet number concentrations (CDNC) on the second day were approximately three times higher than the CDNC measured on the first day. Using the parcel model to separate the influence of the differences in gust velocities, we estimate from the vertically integrated cloud light scattering measurements a 6% increase in the cloud albedo principally due to the increase in the carbonaceous components on the second day. Assuming no additional absorption by this aerosol, a 6% albedo increase translates to a local daytime radiative cooling of ∼ 12 W m −2 . This reCorrespondence to: W. R. Leaitch (richard.leaitch@ec.gc.ca) sult provides observational evidence that the role of anthropogenic carbonaceous components in the cloud albedo effect can be much larger than that of anthropogenic sulphate, as some global simulations have indicated.

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“…The contribution of organic carbon to particulate matter emitted from an ocean-going vessel was estimated by Agrawal et al (2008) to be 15% of the total PM mass. In the present study direct fumigation of the instruments from one of the three platforms involved in the study resulted in sharp increases in concentrations of small particulates, SO 2 , and organic carbon, with little particulate sulphate (Phinney et al, 2006) as a result of the short time between emission and measurement of the plume, leaving little time for oxidation of SO 2 to sulphate. However it points to the importance of organic carbon emissions from ocean-going ships, and moves us to investigate the impacts of these organics on the evolution of the aerosol and on CCN concentrations in the marine atmosphere.…”

Section: Introductionmentioning

confidence: 98%

Contributions from DMS and ship emissions to CCN observed over the summertime North Pacific

et al. 2010

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Abstract. Measurements of cloud condensation nuclei (CCN) made over the North Pacific Ocean in July 2002 are analysed with concurrent measurements of aerosol number, mass and composition. Overall the CCN are controlled by the sulphate, including one case that suggests particle nucleation and growth resulting from dimethyl sulphide oxidation that enhanced CCN concentrations. Hourly CCN concentrations are correlated with concentrations of sulphate plus methanesulphonic acid (MSA) over the entire study period (r 2 =0.43 and 0.52 for supersaturations of 0.34% and 0.19%, respectively), and are not well correlated with other organics (r 2 <0.2). One case study reveals elevated mass and number concentrations of ultrafine and fine organic particles due to regional ship emissions, identified through quadrupole aerosol mass spectrometer (Q-AMS) measurements, during which organic mass concentrations are correlated with CCN values (r 2 =0.39 and 0.46 for supersaturations of 0.19% and 0.34%, respectively). The evolution of the time series and mass distributions of organics, sulphate and MSA over this timeframe indicate that the regional distribution of small, diffuse ship-sourced organic particles act as condensation sites for sulphur species, resulting in a subsequent increase in number concentrations of CCN. We conclude that, where present, direct emissions of anthropogenic organic particles may exert a strong control on marine CCN concentrations once diffused into the marine atmosphere, by acting as condensation sites for biogenic and anthropogenic sulphur species.

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Characterization of the aerosol over the sub-arctic north east Pacific Ocean

Cited by 102 publications

References 49 publications

Comprehensive Simultaneous Shipboard and Airborne Characterization of Exhaust from a Modern Container Ship at Sea

Comprehensive Simultaneous Shipboard and Airborne Characterization of Exhaust from a Modern Container Ship at Sea

Cloud albedo increase from carbonaceous aerosol

Contributions from DMS and ship emissions to CCN observed over the summertime North Pacific

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