Investigating the contribution of shipping emissions to atmospheric PM 2.5 using a combined source apportionment approach * Jianlei Lang * , Ying Zhou, Dongsheng Chen ** , Xiaofan Xing, Lin Wei, Xiaotong Wang, Na Zhao, Yanyun Zhang, Xiurui Guo, Lihui Han, Shuiyuan Cheng Key Laboratory of Beijing on Regional Air Pollution Control, College of Environmental & Energy Engineering, Beijing University of Technology, Beijing 100124, China article info Article history: Received 17 February 2017 Received in revised form 25 June 2017 Accepted 26 June 2017 Keywords: Shipping emissions WRF-CMAQ Source apportionment PCA Fine particle Qinhuangdao abstract Many studies have been conducted focusing on the contribution of land emission sources to PM 2.5 in China; however, little attention had been paid to other contributions, especially the secondary contri- butions from shipping emissions to atmospheric PM 2.5 . In this study, a combined source apportionment approach, including principle component analysis (PCA) and WRF-CMAQ simulation, was applied to identify both primary and secondary contributions from ships to atmospheric PM 2.5 . An intensive PM 2.5 observation was conducted from April 2014 to January 2015 in Qinhuangdao, which was close to the largest energy output port of China. The chemical components analysis results showed that the primary component was the major contributor to PM 2.5 , with proportions of 48.3%, 48.9%, 55.1% and 55.4% in spring, summer, autumn and winter, respectively. The secondary component contributed higher fractions in summer (48.2%) and winter (36.8%), but had lower percentages in spring (30.1%) and autumn (32.7%). The hybrid source apportionment results indicated that the secondary contribution (SC) of shipping emissions to PM 2.5 could not be ignored. The annual average SC was 2.7%, which was comparable to the primary contribution (2.9%). The SC was higher in summer (5.3%), but lower in winter (1.1%). The primary contributions to atmospheric PM 2.5 were 3.0%, 2.5%, 3.4% and 2.7% in spring, summer, autumn and winter, respectively. As for the detailed chemical components, the contributions of shipping emissions were 2.3%, 0.5%, 0.1%, 1.0%, 1.7% and 0.1% to elements & sea salt, primary organic aerosol (POA), element carbon (EC), nitrate, sulfate and secondary organic carbon (SOA), respectively. The results of this study will further the understanding of the implications of shipping emissions in PM 2.5 pollution. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction PM 2.5 (i.e., fine particles with an aerodynamic diameter smaller than 2.5 mm) is the major air pollutant in most areas of China. It has a significant influence on human health (Kollanus et al., 2017; Qi et al., 2017) and visibility degradation (Zhou et al., 2015a). It is necessary to effectively reduce the atmospheric PM 2.5 concentra- tion to mitigate those adverse effects. Understanding the contri- butions of different emission sources to PM 2.5 is an important basis for making effective PM 2.5 pollution mitigation measures. During the past decade, many studies have been conducted to investigate the contributions from sources on land, such as motor vehicles (Abu-Allaban et al., 2007), industry (Bari and Kindzierski, 2016) and biomass burning (Li et al., 2014; Long et al., 2016). However, the influence of emissions from ships, which are considered as “mobile power plants”, received little attention. Receptor models were useful methods to identify the contri- butions of emission sources to atmospheric PM 2.5 (Hua et al., 2015; Song et al., 2006; Zhang et al., 2014b). Some studies have been conducted to obtain the contribution of shipping emissions using various apportionment approaches. For example, Tao et al. (2017) identified the contribution sources for PM 2.5 in Guangzhou and Zhuhai based on a positive matrix factorization (PMF) analysis, indicating that the primary contribution of shipping emissions to atmospheric PM 2.5 was >17% in the two cities. Wang et al. (2016) found that shipping emissions contributed 6.3% (primary contri- bution) of the atmospheric PM in the northern East China Sea, also * This paper has been recommended for acceptance by Eddy Y. Zeng. * Corresponding author. ** Corresponding author. E-mail addresses: jllang@bjut.edu.cn (J. Lang), dschen@bjut.edu.cn (D. Chen). Contents lists available at ScienceDirect Environmental Pollution journal homepage: www.elsevier.com/locate/envpol http://dx.doi.org/10.1016/j.envpol.2017.06.087 0269-7491/© 2017 Elsevier Ltd. All rights reserved. Environmental Pollution 229 (2017) 557e566