Impacts of shipping emissions on PM 2.5 pollution in China

• Published in: Atmospheric chemistry and physics Vol. 18; no. 21; pp. 15811 - 15824
• Main Authors: Lv, Zhaofeng, Liu, Huan, Ying, Qi, Fu, Mingliang, Meng, Zhihang, Wang, Yue, Wei, Wei, Gong, Huiming, He, Kebin
• Format: Journal Article
• Language: English; Japanese
• Published: 02-11-2018
• ISSN: 1680-7324; 1680-7324
• DOI: 10.5194/acp-18-15811-2018

With the fast development of seaborne trade and relatively more efforts on
reducing emissions from other sources in China, shipping emissions contribute
more and more significantly to air pollution. In this study, based on a
shipping emission inventory with high spatial and temporal resolution within
200 nautical miles (Nm) to the Chinese coastline, the Community Multiscale
Air Quality (CMAQ) model was applied to quantify the impacts of the shipping
sector on the annual and seasonal concentrations of PM2.5 for the base
year 2015 in China. Emissions within 12 Nm accounted for
51.2 %–56.5 % of the total shipping emissions, and the distinct
seasonal variations in spatial distribution were observed. The modeling
results showed that shipping emissions increased the annual averaged
PM2.5 concentrations 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 only coastal areas but also the inland areas hundreds of
kilometers (up to 960 km) away from the sea. The impacts on the PM2.5
showed obvious seasonal variations, and patterns in the north and south of
the Yangtze River were also quite different. In addition, since the onshore
wind can carry ship pollutants to inland areas, the daily contributions of
shipping emissions in onshore flow days were about 1.8–2.7 times higher than
those in the rest of the days. A source-oriented CMAQ was used to estimate the
contributions of shipping emissions from maritime areas within 0–12, 12–50,
50–100 and 100–200 Nm to PM2.5 concentrations. The results
indicated that shipping emissions within 12 Nm were the dominant
contributor,
with contributions 30 %–90 % of the total impacts induced by
emissions within 200 Nm, while a relatively high contribution
(40 %–60 %) of shipping emissions within 20–100 Nm was
observed in the north of the YRD region and south of Lianyungang, due to the
major water traffic lanes far from land. The results presented in this work
implied that shipping emissions had significant influence on air quality in
China, and to reduce its pollution, the current Domestic Emission Control
Area (DECA) should be expanded to at least 100 Nm from the coastline.