Long-range transport of particulate polycyclic aromatic hydrocarbons at Cape Hedo remote island site in the East China Sea between 2005 and 2008

Abstract

Particle-associated polycyclic aromatic hydrocarbons (PAHs) in outflow from East Asia were observed at Cape Hedo, Okinawa, Japan between 2005 and 2008. The filter samples of the total suspended particles were analyzed by means of gas chromatographymass spectrometry. The total concentration of fourteen 3-7-ring PAHs was 0.01-24 ng m ). The average PAH concentration increased in the winter-spring season and decreased in the summer-fall season. The average benzo(a)pyrene to benzo(e)pyrene ratio was 0.49 in the winter-spring season and was lower than the literature values for East Asian cities in the same season. This result shows that aging of organic aerosol particles proceeds during long-range transport from East Asia. In the Asian Pacific region, these pollutants are transported from East Asia in the winter-spring season, whereas clean air mass is transported from the Pacific Ocean in the summer-fall season.

Transported and Local Organic Aerosols over Fukuoka, Japan

“…The average value of spring (0.657 ± 0.399) or winter 2010 (0.745 ± 0.201) was higher than that of summer 2011 (0.273 ± 0.315) (p < 0.05 in both comparisons). The results of the spring and winter seasons indicate that 65 to 75 % of total PAHs observed at the FC site are transported, whereas 25 to 35 % of total PAHs observed at the FC site are emitted from local (Sato et al, 2008). These values observed at island sites around the East China Sea are very close to the average ΣPAHs observed at the FI site in this study.…”

“…According to International Agency for Research on Cancer (2012), benzo(a)pyrene is carcinogenic, and dibenz(a,h)anthracene is probably carcinogenic. The maximum total PAH levels observed during air pollution events at Cape Hedo on Okinawa Island were comparable with the average total PAH levels measured at urban sites (Sato et al, 2008;Yoshino et al, 2011), indicating that transported and local pollutants would make comparable contributions to the atmosphere of megacities around this area.…”

“…The procedure of fractionation is described in detail elsewhere (Sato et al, 2008). PAHs and n-alkanes were both contained in the first fraction of the n-hexane solution.…”

One-year observations of carbonaceous and nitrogenous components and major ions in the aerosols from subtropical Okinawa Island, an outflow region of Asian dusts

“…Cape Hedo is located on the northern edge of Okinawa and has been used as a supersite of Atmospheric Brown Clouds (ABC) project to study the atmospheric transport of Chinese aerosols and their chemical transformation in East Asia (Takami et al, 2007). In the Asian Pacific region, the East Asian monsoon dominates in winter to spring, whereas the monsoon from the Pacific Ocean dominates in summer to fall (Sato et al, 2009), therefore, continental air masses from East Asian countries including Russia, Mongolia, China, and Korea generally arrive over Okinawa during winter and spring.…”

“…We discuss the seasonal changes of these components and transformations of organic aerosol (OA) during the longrange transport of Asian aerosols. Many studies related to the atmospheric chemistry have been conducted at Cape Hedo (Sato et al, 2009;Wang et al, 2009;Zhang et al, 2003;Jaffe et al, 2005;Verma et al, 2011;Lun et al, 2009;Yamamoto and Kawamura, 2011;Ueda et al, 2011;Arakaki et al, 2006;Handa et al, 2010;Mochida et al, 2010). However, no studies were conducted for a long-term measurement of OC, EC, WSOC, WSTN, WSON and major ions in atmospheric aerosols from Cape Hedo, Okinawa Island.…”