title: PM₂.₅-bound oxygenated PAHs, nitro-PAHs and parent-PAHs from the atmosphere of a Chinese megacity: seasonal variation, sources and cancer risk assessment.
abstract: Polycyclic aromatic compounds (PACs) in air particulate matter contribute considerably to the health risk of air pollution. The objectives of this study were to assess the occurrence and variation in concentrations and sources of PM2.5-bound PACs [Oxygenated PAHs (OPAHs), nitro-PAHs and parent-PAHs] sampled from the atmosphere of a typical Chinese megacity (Xi'an), to study the influence of meteorological conditions on PACs and to estimate the lifetime excess cancer risk to the residents of Xi'an (from inhalation of PM2.5-bound PACs). To achieve these objectives, we sampled 24-h PM2.5 aerosols (once in every 6 days, from 5 July 2008 to 8 August 2009) from the atmosphere of Xi'an and measured the concentrations of PACs in them. The PM2.5-bound concentrations of Σcarbonyl-OPAHs, ∑hydroxyl+carboxyl-OPAHs, Σnitro-PAHs and Σalkyl+parent-PAHs ranged between 5-22, 0.2-13, 0.3-7, and 7-387 ng m(-3), respectively, being markedly higher than in most western cities. This represented a range of 0.01-0.4% and 0.002-0.06% of the mass of organic C in PM2.5 and the total mass of PM2.5, respectively. The sums of the concentrations of each compound group had winter-to-summer ratios ranging from 3 to 8 and most individual OPAHs and nitro-PAHs had higher concentrations in winter than in summer, suggesting a dominant influence of emissions from household heating and winter meteorological conditions. Ambient temperature, air pressure, and wind speed explained a large part of the temporal variation in PACs concentrations. The lifetime excess cancer risk from inhalation (attributable to selected PAHs and nitro-PAHs) was six fold higher in winter (averaging 1450 persons per million residents of Xi'an) than in summer. Our results call for the development of emission control measures.
authors.affiliation: Geographic Institute, University of Bern, Hallerstrasse 12, 3012 Bern, Switzerland. Electronic address: benjamin.bandowe@giub.unibe.ch.
authors.forename: Benjamin A Musa
authors.initials: BA
authors.lastname: Bandowe
authors.affiliation: Geographic Institute, University of Bern, Hallerstrasse 12, 3012 Bern, Switzerland; Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany; Multiphase Chemistry Department, Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128 Mainz, Germany.
authors.forename: Hannah
authors.initials: H
authors.lastname: Meusel
authors.affiliation: Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany; Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232 Villigen PSI, Switzerland.
authors.forename: Ru-Jin
authors.initials: RJ
authors.lastname: Huang
authors.affiliation: School of Public Health & Primary Care, Chinese University of Hong Kong, Hong Kong; Key Laboratory of Aerosol Science & Technology, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, 10 Fenghui South Road, High-Tech Zone, 710075 Xi'an, China. Electronic address: kfho@cuhk.edu.hk.
authors.forename: Kinfai
authors.initials: K
authors.lastname: Ho
authors.affiliation: Key Laboratory of Aerosol Science & Technology, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, 10 Fenghui South Road, High-Tech Zone, 710075 Xi'an, China.
authors.forename: Junji
authors.initials: J
authors.lastname: Cao
authors.affiliation: Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128 Mainz, Germany.
authors.forename: Thorsten
authors.initials: T
authors.lastname: Hoffmann
authors.affiliation: Geographic Institute, University of Bern, Hallerstrasse 12, 3012 Bern, Switzerland.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Wilcke
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000706:statistics & numerical data*; D001272:Atmosphere / Q000737:chemistry; D002681:China / Q000453:epidemiology; D002947:Cities / Q000706:statistics & numerical data; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D006801:Humans; D009369:Neoplasms / Q000453:epidemiology*; D052638:Particulate Matter / Q000032:analysis*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D018570:Risk Assessment; D012621:Seasons
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D011084:Polycyclic Aromatic Hydrocarbons
keywords: Cancer risk; China; Nitro-PAHs; Oxygenated PAHs; PAHs; PM(2.5)