Atmos. Chem. Phys., 20, 14581–14595, 2020 https://doi.org/10.5194/acp-20-14581-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Nationwide increase of polycyclic aromatic hydrocarbons in ultrafine particles during winter over China revealed by size-segregated measurements Qingqing Yu1, Xiang Ding1,4, Quanfu He1, Weiqiang Yang5, Ming Zhu1,2, Sheng Li1,2, Runqi Zhang1,2, Ruqin Shen1, Yanli Zhang1,3,4, Xinhui Bi1,4, Yuesi Wang3,6, Ping’an Peng1,4, and Xinming Wang1,2,3,4 1State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China 2University of Chinese Academy of Sciences, Beijing 100049, China 3Center for Excellence in Regional Atmospheric Environment, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China 4Guangdong-Hong Kong-Macao Joint Laboratory for Environmental Pollution and Control, Guangzhou Institute of Geochemistry, Chinese Academy of Science, Guangzhou 510640, China 5Guangdong Provincial Academy of Environmental Science, Guangzhou 510045, China 6State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China Correspondence: Xinming Wang (
[email protected]), and Xiang Ding (
[email protected]) Received: 10 June 2020 – Discussion started: 22 June 2020 Revised: 13 October 2020 – Accepted: 14 October 2020 – Published: 1 December 2020 3 Abstract. Polycyclic aromatic hydrocarbons (PAHs) are BaPeq (8.48 vs. 1.34 ng/m / and PAHs’ inhalation cancer risk toxic compounds in the atmosphere and have adverse effects (7.4 × 10−4 vs.