Relative Influence of Trans-Pacific and Regional Atmospheric Transport of PAHs in the Pacific Northwest, U.S

• Published in: Environmental science & technology Vol. 49; no. 23; pp. 13807 - 13816
• Main Authors: Lafontaine, Scott, Schrlau, Jill, Butler, Jack, Jia, Yuling, Harper, Barbara, Harris, Stuart, Bramer, Lisa M, Waters, Katrina M, Harding, Anna, Simonich, Staci L. Massey
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 01-12-2015
• Subjects: Air Pollutants - analysis; Asia; Carbon; Carbon - analysis; Carbon Dioxide - analysis; Correlation analysis; Emissions control; Environmental Monitoring - methods; Nitric Oxide - analysis; Northwestern United States; Oregon; Particulate Matter - analysis; Polycyclic aromatic hydrocarbons; Polycyclic Aromatic Hydrocarbons - analysis; Pyrenes - analysis; Sea level; Seasons; Sulfur Dioxide - analysis; USA, Cascade Mts; INW, Asia; USA, Columbia R
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/acs.est.5b00800

The relative influences of trans-Pacific and regional atmospheric transport on measured concentrations of polycyclic aromatic hydrocarbons (PAHs), PAH derivatives (nitro- (NPAH) and oxy-(OPAH)), organic carbon (OC), and particulate matter (PM) less than 2.5 μm in diameter (PM2.5) were investigated in the Pacific Northwest, U.S. in 2010–2011. Ambient high volume PM2.5 air samples were collected at two sites in the Pacific Northwest: (1.) Mount Bachelor Observatory (MBO) in the Oregon Cascade Range (2763 m above sea level (asl)) and 2.) Confederated Tribes of the Umatilla Indian Reservation (CTUIR) in the Columbia River Gorge (CRG) (954 m asl). At MBO, the 1,8-dinitropyrene concentration was significantly positively correlated with the time a sampled air mass spent over Asia, suggesting that this NPAH may be a good marker for trans-Pacific atmospheric transport. At CTUIR, NO x , CO2, and SO2 emissions from a 585 MW coal fired power plant, in Boardman OR, were found to be significantly positively correlated with PAH, OPAH, NPAH, OC, and PM2.5 concentrations. By comparing the Boardman Plant operational time frames when the plant was operating to when it was shut down, the plant was found to contribute a large percentage of the measured PAH (67%), NPAH (91%), OPAH (54%), PM2.5 (39%), and OC (38%) concentrations at CTUIR and the CRG prior to Spring 2011 and likely masked trans-Pacific atmospheric transport events to the CRG. Upgrades installed to the Boardman Plant in the spring of 2011 dramatically reduced the plant’s contribution to PAH and OPAH concentrations (by ∼72% and ∼40%, respectively) at CTUIR and the CRG, but not NPAH, PM2.5 or OC concentrations.