Atmos. Chem. Phys., 18, 15811–15824, 2018 https://doi.org/10.5194/acp-18-15811-2018 © Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License. Impacts of shipping emissions on PM2:5 pollution in China Zhaofeng Lv1,2, Huan Liu1,2, Qi Ying3, Mingliang Fu4,5, Zhihang Meng1,2, Yue Wang1,2, Wei Wei6, Huiming Gong7, and Kebin He1,2 1State Key Joint Laboratory of ESPC, School of the Environment, Tsinghua University, Beijing 100084, China 2State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China 3Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843, USA 4State Key Laboratory of environmental criteria and risk assessment (SKLECRA), Chinese research academy of environmental sciences, Beijing 100012, China 5Vehicle emission control center, Ministry of ecology and environment of the people’s republic of China, Beijing 100012, China 6Department of Environmental Science and Engineering, Beijing University of Technology, Beijing 100124, China 7National Laboratory of Automotive Performance & Emission Test, Beijing Institute of Technology, Beijing 100081, China Correspondence: Huan Liu ([email protected]) Received: 29 May 2018 – Discussion started: 27 June 2018 Revised: 3 October 2018 – Accepted: 15 October 2018 – Published: 2 November 2018 Abstract. With the fast development of seaborne trade and CMAQ was used to estimate the contributions of shipping relatively more efforts on reducing emissions from other emissions from maritime areas within 0–12, 12–50, 50–100 sources in China, shipping emissions contribute more and and 100–200 Nm to PM2:5 concentrations. The results indi- more significantly to air pollution. In this study, based on cated that shipping emissions within 12 Nm were the dom- a shipping emission inventory with high spatial and tempo- inant contributor, with contributions 30 %–90 % of the total ral resolution within 200 nautical miles (Nm) to the Chinese impacts induced by emissions within 200 Nm, while a rela- coastline, the Community Multiscale Air Quality (CMAQ) tively high contribution (40 %–60 %) of shipping emissions model was applied to quantify the impacts of the shipping within 20–100 Nm was observed in the north of the YRD re- sector on the annual and seasonal concentrations of PM2:5 gion and south of Lianyungang, due to the major water traffic for the base year 2015 in China. Emissions within 12 Nm ac- lanes far from land. The results presented in this work im- counted for 51.2 %–56.5 % of the total shipping emissions, plied that shipping emissions had significant influence on air and the distinct seasonal variations in spatial distribution quality in China, and to reduce its pollution, the current Do- were observed. The modeling results showed that shipping mestic Emission Control Area (DECA) should be expanded emissions increased the annual averaged PM2:5 concentra- to at least 100 Nm from the coastline. tions in eastern China up to 5.2 µg m−3, and the impacts in YRD (Yangtze River Delta) and PRD (Pearl River Delta) were much greater than those in BTH (Beijing–Tianjin– Hebei). Shipping emissions influenced the air quality in not 1 Introduction only coastal areas but also the inland areas hundreds of kilo- meters (up to 960 km) away from the sea. The impacts on The marine transport sector is regarded as an important source of air pollutants, emitting carbon monoxide (CO), sul- the PM2:5 showed obvious seasonal variations, and patterns in the north and south of the Yangtze River were also quite fur oxides (SOx), nitrogen oxides (NOx), particulate matter different. In addition, since the onshore wind can carry ship (PM), volatile organic compounds (VOCs) and greenhouse pollutants to inland areas, the daily contributions of shipping gas (Corbett and Fischbeck, 1997). The pollutants emitted emissions in onshore flow days were about 1.8–2.7 times from ships can be carried in the atmosphere over several hun- higher than those in the rest of the days. A source-oriented dreds of kilometers inland by the onshore flow and signif- icantly affect the inland air quality, especially with higher Published by Copernicus Publications on behalf of the European Geosciences Union. 15812 Z. Lv et al.: Impacts of shipping emissions on PM2:5 pollution in China aerosol concentrations. In recent years, shipping emissions is approved as a 12 Nm zone along the coastline in Bohai have become one of the fast-growing sources due to the in- Rim, YRD and PRD regions, and the sulfur content of any crease in global shipping business in the long term. It is oil used on-board vessels entering the DECA should not ex- expected to contribute to 17 % of global CO2 emissions in ceed 0.5 % after 2019. Whether reducing shipping emissions 2050 (Cames et al., 2015). Liu et al. (2016) found that ship- in the 12 Nm DECA alone is enough to prevent ship-related ping emissions in East Asia caused 14 500–37 500 prema- air pollution or not becomes an important issue. A study re- ture deaths in 2013, the amount of which had doubled since ported that even if the DECA along the coast of PRD were 2005. In China, the severe haze pollution remains a signif- expanded to 200 Nm, it would not obviously reduce the air icant concern because of its high frequency of occurrence, pollution from shipping emissions compared with the effects especially in megacities, where ships can contribute 20 %– of a 12 Nm DECA (Liu et al., 2018a). However, for other 30 % of the total PM2:5 during ship-plume-influenced peri- coastal regions or cities in China, the rationality of the cur- ods (Fu and Chen, 2017; Liu et al., 2017b). Therefore, it is rent DECA policy is unknown. necessary to quantify the effects of shipping emissions on the In this study, based on the shipping emission inventory air quality at local and regional scale. with a high spatial and temporal resolution within 200 Nm of The influence of ship traffic on air quality varies in dif- the Chinese coast, the annual and seasonal impacts of ship- ferent areas, due to differences in many complicated factors, ping emissions on PM2:5 concentrations in eastern areas and such as meteorological conditions and emission intensities some key regions and cities of China were investigated in from ships and land-based sources. In Europe, although the detail. The impacts of metrological conditions on PM2:5 pol- increase in PM2:5 concentrations caused by emissions from lution induced by shipping emissions were further analyzed. ships is quite small, their relative contribution is large be- In addition, a source-oriented chemical transport model was cause of the low background PM2:5 concentrations in these applied to estimate contributions of shipping emissions emit- regions (Viana et al., 2009; Aksoyoglu et al., 2016; Marelle et ted from different maritime areas, including within 12, 12– al., 2016). In China, although high concentrations of reactive 50, 50–100 and 100–200 Nm of the coastline, to the inland air pollutants probably cause higher secondary PM (e.g., sul- PM2:5 concentrations. The results of this work provided sev- fate, nitrate) concentrations from shipping emissions, their eral suggestions for the development of DECA and related relative contributions are lower due to larger emissions of policies. land-based sources (Lang et al., 2017). However, the stud- ies in China only focus on the impacts of shipping emissions on a small scale, typically located in Bohai Rim area, YRD 2 Methodology (Yangtze River Delta) and PRD (Pearl River Delta) regions including several ports and limited surrounding areas, which The models used in this study were the Weather Research are not available to comprehensively determine the charac- and Forecasting Model (WRF) with version 3.8.1 and the teristics of PM2:5 pollution caused by shipping emissions in Community Multiscale Air Quality (CMAQ) model with ver- the entire eastern coastal areas of China (Fan et al., 2016; sion 5.2, which were developed by US NCAR (National Cen- Chen et al., 2017; Tao et al., 2017; Liu et al., 2017b, 2018a, ter for Atmospheric Research) and US EPA (Environmental b) Protection Agency), respectively. To assess the influences of While reducing emissions from land-based sources, such shipping emissions on air quality, the WRF–CMAQ system as on-road vehicles and power plants, requires only provin- was applied to simulate the PM2:5 with (base case) and with- cial and national legislation and regulations, legislation to ef- out shipping emissions (no ship case) during January, April, fectively control shipping emissions is a big challenge due July and October 2015, which represented winter, spring, to international maritime trade. The International Maritime summer and fall, respectively, with 3 days of spin-up time Organization (IMO) is devoted to protecting the marine envi- for each run. As shown in Fig. 1, the modeling domain cov- ronment through prevention of sea pollution caused by ships. ered all of China and some parts of East Asia with a hor- It has published the International Convention for the Pre- izontal resolution of 36 km × 36 km, including three highly vention of Marine Pollution from Ships (MARPOL) Annex developed city clusters (BTH, YRD, PRD). A total of 13 VI (IMO, 2017), in which four typical maritime regions are highly populated coastal cities were selected to further dis- designated as Emission Control Areas (ECAs). The North cuss their air quality impacts from shipping emissions, in- and Baltic seas in Europe are defined as Sulfur Emission cluding Dalian, Tangshan (in BTH), Tianjin (in BTH), Yan- Control Areas (SECAs), where only low-sulfur-content fuel tai, Qingdao, Lianyungang, Hangzhou (in YRD), Shanghai (<0:1 %) has been allowed to be used since 1 January 2015.