title: Azaarenes in fine particulate matter from the atmosphere of a Chinese megacity.
abstract: Azaarenes (AZAs) are toxicologically relevant organic compounds with physicochemical properties that are significantly different from the well-studied polycyclic aromatic hydrocarbons (PAHs). However, little is known about their concentrations, seasonal variations, fate, and relationship with PAHs in air. This paper reports the temporal variations in the concentrations and composition patterns of AZAs in PM2.5 that was sampled once per 6 days from outdoor air of Xi'an, China from July 2008 to August 2009. The concentrations of the ∑AZAs, quinoline (QUI), benzo[h]quinoline (BQI), and acridine (ACR) in PM2.5 were 213-6441, 185-520, 69-2483, and 10-3544 pg m(-3), respectively. These concentrations were higher than those measured in urban areas of Western Europe. AZA compositional patterns were dominated by BQI and ACR. The high concentration of AZAs, high AZA/related PAH ratio, and the dominance of three-ring AZAs (BQI and ACR) in PM2.5 of Xi'an are all in contrast to observations from Western European and North American cities. This contrast likely reflects differences in coal type and the more intense use of coal in China. The PM2.5-bound concentration of AZA in winter season (W) was higher than during the summer season (S) with W/S ratios of 5.7, 1.4, 4.1, and 13, for ∑AZAs, QUI, BQI, and ACR, respectively. Despite their significantly different physicochemical properties, AZAs were significantly (p < 0.05) positively correlated with their related PAHs and pyrogenic elemental carbon. The changes in AZA concentrations were positively correlated with ambient pressure but negatively correlated with ambient temperature, wind speed, and relative humidity. This trend is similar to that observed for the related PAHs. We conclude that Xi'an and possibly other Chinese cities have higher emission of AZAs into their atmosphere because of the more pronounced use of coal. We also conclude that in spite of differences in physicochemical properties between AZAs and related PAHs, the atmospheric dynamics and relationships with meteorological factors of both compound groups are similar.
authors.affiliation: Institute of Geography, University of Bern, Hallerstrasse 12, 3012, Bern, Switzerland. benjamin.bandowe@giub.unibe.ch.|Oeschger Centre for Climate Change Research, University of Bern, Falkenplatz 16, 3012, Bern, Switzerland. benjamin.bandowe@giub.unibe.ch.
authors.forename: Benjamin A Musa
authors.initials: BA
authors.lastname: Bandowe
authors.affiliation: 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: Key Laboratory of Aerosol Chemistry & Physics, Institute of Earth Environment, Chinese Academy of Sciences, 10 Fenghui South Road, 710075, Xi'an, China.|Centre for Atmospheric and Marine Sciences, Xiamen Huaxia University, Xiamen, 361024, China.|Laboratory of Atmospheric Chemistry, Paul Scherrer Institute, 5232, Villigen, Switzerland.|Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany.
authors.forename: Rujin
authors.initials: R
authors.lastname: Huang
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: Key Laboratory of Aerosol Chemistry & Physics, Institute of Earth Environment, Chinese Academy of Sciences, 10 Fenghui South Road, 710075, Xi'an, China.
authors.forename: Junji
authors.initials: J
authors.lastname: Cao
authors.affiliation: Jockey Club School of Public Health & Primary Care, The Chinese University of Hong Kong, Sha Tin, Hong Kong.
authors.forename: Kinfai
authors.initials: K
authors.lastname: Ho
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001372:Aza Compounds / Q000032:analysis; D002681:China; D002947:Cities; D003031:Coal; D004784:Environmental Monitoring; D052638:Particulate Matter / Q000032:analysis*; D012621:Seasons; D014919:Wind
chemical_list: D000393:Air Pollutants; D001372:Aza Compounds; D003031:Coal; D052638:Particulate Matter
keywords: Azaarenes; Chinese megacity; Meteorological conditions; PAHs; PM2.5; Seasonal change