Influence of Ship Emissions on Urban Air Quality: A Comprehensive Study Using Highly Time-Resolved Online Measurements and Numerical Simulation in Shanghai.

Shanghai has become an international shipping center in the world. In this study, the multiyear measurements and the high resolution air quality model with hourly ship emission inventory were combined to determine the influence of ship emissions on urban Shanghai. The aerosol time-of-flight mass spectrometer (ATOFMS) measurements were carried out at an urban site from April 2009 to January 2013. During the entire sampling time, most of the half-hourly averaged number fractions of primary ship emitted particles varied between 1.0-10.0%. However, the number fraction could reach up to 50% during the ship plume cases. Ship-plume-influenced periods usually occurred in spring and summer. The simulation of Weather Research and Forecasting/Community Multiscale Air Quality model (WRF/CMAQ) with hourly ship emission inventory provided the highly time-resolved concentrations of ship-related air pollutants during a ship plume case. It showed ships could contribute 20-30% (2-7 µg/m3) of the total PM2.5 within tens of kilometers of coastal and riverside Shanghai during ship-plume-influenced periods. Our results showed that ship emissions have substantial contribution to the air pollution in urban Shanghai. The control measures of ship emission should be taken considering its negative environment and human health effects.

Spatial and Seasonal Dynamics of Ship Emissions over the Yangtze River Delta and East China Sea and Their Potential Environmental Influence.

The Yangtze River Delta (YRD) port cluster is one of five major port clusters in China and is home to Shanghai port, the largest port worldwide. In this study, an automatic identification system-based model was built to estimate the ship exhaust emissions in the YRD and the East China Sea within 400 km of the coastline. In 2010, the total emissions of SO2, NOX, and PM2.5 were 3.8 × 10(5) tonnes/yr, 7.1 × 10(5) tonnes/yr, and 5.1 × 10(4) tonnes/yr, respectively. More than 60% and 85% of the ship emissions occurred within 100 km and 200 km of the coastline, respectively. Ship emissions also showed distinct seasonal variability. The emission of SO2 and NOX by ships in hot spots, such as ports and vessel traffic hubs was much higher than that on land, with maximum SO2 and NOX intensities from ships that were 36 times and 17 times greater, respectively, than the maximal land-based emissions. The potential impact of ship emissions at six hot spots on the surrounding atmospheric environment was estimated with the HYSPLIT model. Our study demonstrated that ship emissions have an important impact on both the entire YRD region and on greater East China.