Size-Segregated Inorganic and Organic Components of PM in the Communities of the Los Angeles Harbor

Abstract

The Los Angeles Ports complex consists of the port of Long Beach and the port of Los Angeles. Due to the high levels of particulate matter (PM) emitted from many sources in the vicinity of these ports and to their projected massive expansion, the Harbor area will be the focus of future governmental regulations. This study aims to characterize the physicochemical properties of PM at locations influenced by port-affiliated sources. PM samples were collected concurrently at six sites in the southern Los Angeles basin for a 7 week period between March and May 2007. Four sites were set-up within the communities of Wilmington and Long Beach; one site was located at a background location near the harbors of the Los Angeles port; the sixth site, near downtown Los Angeles, was chosen to represent a typical urban area. Coarse (PM _{2.5 − 10} ), accumulation (PM _{0.25 − 2.5} ), and quasi-ultrafine (PM _0.25 ) mode particles were collected at each site. Samples were analyzed for organic and elemental carbon content (OC and EC, respectively), organic species, inorganic ions, water soluble and total elements. The carbon preference index (CPI) for quasi-UF and accumulation mode particles varied from 0.65 to 1.84 among sites, which is in the range of previous findings in areas with high influence of anthropogenic sources. The ratio of hopanes to EC and hopanes to OC over all the sites were in the range of previous roadside measurements near freeways with variable volumes of diesel truck traffic. High overall correlation of vanadium with nickel (R = 0.9) and a considerable gradient of vanadium centrations with distance to the port, suggest marine vessels as the major sources of these elements.

This research was supported by the Southern California Particle Center (SCPC), funded by EPA under the STAR program through Grant RD-8324-1301-0 to the University of Southern California. The research described herein has not been subjected to the agency's required peer and policy review and therefore does not necessarily reflect the views of the agency, and no official endorsement should be inferred. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use. We thank the following staff at the Wisconsin State Lab of Hygiene (WSLH) for conducting EC-OC, ion chromatography, GC/MS, and ICPMS analysis: Brandon Shelton, Jeff DeMinter, Martin Shafer, Pat Gorski, and Joel Overdier. We are thankful for the port of Long Beach, Dinesh Mohda, and the staff at the Long Beach Job Corps Center, Mr. Baltazar Alvarez (and, of course, South Coast AQMD) for the help in the sample collection at the Sites 2, 3, and 5.

Notes

^a Brewer (1975).

^b WSS is based on ICP-MS extraction of the soluble portion of these species.

^c WIS is based on ICP-MS extraction of the total-soluble portion of these species.

^d [Si] has been estimated from [Al], [Si] = 3 x [Al] (Sillanpää et al., 2006).

^a CPI = ΣC (2n + 1)/ΣC(2n), n = 7–20.