title: Concentrations, particle-size distributions, and indoor/outdoor differences of polycyclic aromatic hydrocarbons (PAHs) in a middle school classroom in Xi'an, China.
abstract: Polycyclic aromatic hydrocarbons (PAHs) attached to particulate matter can affect respiratory health, especially the health of children, but information on the air quality in schools is generally lacking. This study investigated the PAH concentrations in a naturally ventilated classroom in Xi'an, China, from 16 to 31 May 2012. Particulate PAH concentrations were measured for samples collected on five-stage cascade impactors deployed inside the classroom and outside. PM2.5-bound PAH concentrations were 53.2 ng m(-3) indoors and 72.9 ng m(-3) outdoors. PAHs attached to very fine particles (VFPs) accounted for ~70% of the total PAHs. The PAH concentrations indoors were affected by the students' activities, cleaning, and smoking, while outdoors, the main sources were motor vehicle emissions and contaminated road dust. Particle-bound PAHs infiltrated the classroom through open windows, but the activities of the students and staff were also associated with an increase of PAHs attached to particles larger than 1.0 µm, most likely through resuspension. Cycles in the sources led to PAH concentrations 2-3 times higher on weekdays compared to weekends, both indoors and outdoors. PAH toxicity risks inside the classroom were substantially lower than those outdoors, and the highest risks were associated with VFPs.
authors.affiliation: Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, China. xuhongmei@mail.xjtu.edu.cn.|Key Lab of Aerosol Chemistry and Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China. xuhongmei@mail.xjtu.edu.cn.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Xu
authors.affiliation: Key Lab of Aerosol Chemistry and Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China.|Laboratoire d'Aerologie, Observatory Midi-Pyrenees, CNRS-Université Paul-Sabatier, Toulouse, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Guinot
authors.affiliation: Key Lab of Aerosol Chemistry and Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China.|School of Human Settlements and Civil Engineering, Xi'an Jiaotong University, Xi'an, China.
authors.forename: Xinyi
authors.initials: X
authors.lastname: Niu
authors.affiliation: Key Lab of Aerosol Chemistry and Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China. jjcao@ieecas.cn.|Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an, China. jjcao@ieecas.cn.
authors.forename: Junji
authors.initials: J
authors.lastname: Cao
authors.affiliation: School of Public Health and Primary Care, The Chinese University of Hong Kong, Hong Kong, China.
authors.forename: Kin Fai
authors.initials: KF
authors.lastname: Ho
authors.affiliation: Department of Environmental Health, School of Publich Health, Fudan University, Shanghai, China.
authors.forename: Zhuohui
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Key Lab of Aerosol Chemistry and Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China.|Hong Kong Premium Services and Research Laboratory, Lai Chi Kok, Kowloon, Hong Kong, China.
authors.forename: Steven Sai Hang
authors.initials: SS
authors.lastname: Ho
authors.affiliation: Key Lab of Aerosol Chemistry and Physics, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an, China.
authors.forename: Suixin
authors.initials: S
authors.lastname: Liu
mesh_terms: D016902:Air Pollution, Indoor / Q000032:analysis*; D002681:China; D004784:Environmental Monitoring; D006802:Human Activities; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D012574:Schools; D012907:Smoking; D001335:Vehicle Emissions
chemical_list: D052638:Particulate Matter; D011084:Polycyclic Aromatic Hydrocarbons; D001335:Vehicle Emissions
keywords: Aerosols; Health risk; Indoor/outdoor ratio; PAHs; School air quality; Size distribution