title: Size distributions of polycyclic aromatic hydrocarbons in the atmosphere and estimation of the contribution of ultrafine particles to their lung deposition.
abstract: This is the first estimation of the contribution of ultrafine particles to the lung deposition of particle-bound polycyclic aromatic hydrocarbons (PAHs) in the atmosphere. The size distributions of nine PAHs (4-6 rings) were measured at roadside and suburban sites in winter in Japan. Deposition efficiencies and fluxes of PAHs in ultrafine mode (<0.12 microm), accumulation mode (0.12-2.1 microm), and coarse mode (>2.1 microm) to the human respiratory tract were calculated using the LUDEP computer-based model. From 10%-15% and 4.2%-6.9% of target PAHs were distributed in the ultrafine mode in the roadside and suburban atmosphere, respectively. The model calculations showed that as much as 18%-19% and 16%-17% of inhaled PAHs are deposited in the alveolar region of the lung for the roadside and suburban atmosphere, respectively. Total deposition fluxes of target PAHs in the alveolar region were about 1.5-fold greater for the roadside atmosphere than for the suburban atmosphere. Importantly, ultrafine particles were shown to contribute as much as 23%-30% and 10%-16% to PAH deposition in the alveolar region for the roadside and suburban atmosphere, respectively, although the contributions of ultrafine particles to the total particulate matter masswere only 2.3% in the roadside atmosphere and 1.3% in the suburban atmosphere. These results indicated that ultrafine particles are significant contributors to the deposition of PAHs into the alveolar region of the lung.
authors.affiliation: The Institute of Basic Environmental Research, Environmental Control Center Co., Ltd., 323-1 Shimo-ongata, Hachioji, Tokyo 192-0154, Japan. ykawanaka@kankyo-kanri.co.jp
authors.forename: Youhei
authors.initials: Y
authors.lastname: Kawanaka
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Tsuchiya
authors.forename: Sun-Ja
authors.initials: SJ
authors.lastname: Yun
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Sakamoto
mesh_terms: D000388:Air / Q000032:analysis / Q000592:standards; D000393:Air Pollutants / Q000032:analysis* / Q000493:pharmacokinetics*; D003198:Computer Simulation; D004784:Environmental Monitoring; D006801:Humans; D007564:Japan; D008168:Lung / Q000187:drug effects* / Q000378:metabolism; D008954:Models, Biological; D010316:Particle Size; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000493:pharmacokinetics*; D012137:Respiratory System / Q000187:drug effects / Q000378:metabolism; D018881:Suburban Health; D014018:Tissue Distribution; D014504:Urban Health
chemical_list: D000393:Air Pollutants; D011084:Polycyclic Aromatic Hydrocarbons