Effects Of Aerosol Physical And Chemical Properties And Shipping Emissions On Regional Air Quality In Shanghai Port

The coastal economy has shown a fast growth in recent years. With an increase in marine transport, the impact of shipping emissions on environment is more and moer apparent. In this study, field measurement campaigns were conducted in Yangshan Port, which is one working area of Shanghai Port-the world’s largest port now. Using the research methods such as aerosol sampling, gaseous pollutant monitoring, heavy fuel oil investigation, and chemical experiment, as well as combination of meteorological data analysis, the characteristics and ship traffic sources identification of aerosols in port area have been systematically studied. The results of this paper are as follows:During the study period, the average hourly SO2and NO2concentrations were29.4and63.7μg m-3, and the average daily concentration of PM2.5was59.7μg m-3. Compared with the mean levels in Shanghai land area, SO2and NO2levels were almost about the same, but much higher peak concentrations of the two gases were observed in Yangshan Port.The averaged concentration of black carbon in PM2.5was1.52μg m-3, and the averaged concentrations of major water soluble ions SO42-, NO3-and NH4+in PM2.5were8.19μg m-3,3.43μg m-3and5.01μg m-3, respectively. The three ions occupied27.83%of the total PM2.5concentration in an average level. The mean concentrations of S, Ni and V in PM2.5were5.94μg m-3,80.02ng m-3and14.47μg m-3, respectively. Due to the significant anthropogenic sources, EFs of elements S and As reached more than1000and some heavy metals also moderately or highly enriched in atmosphere. SO42-, V, Ni and Pb were found tend to accumulate in fine particles. The HYSPLIT backward trajectory analysis revealed that correlations between SO2and NO2under marine and mixing airflows were stronger than under continental airflows, and mass concentration ratio between hybrid coastal and continental airflows was1.6and1.5for V and Ni. In terms of averaged contents in heavy fuel oil samples, V ranked top of the12detected elements. Also V was found to be highly correlated with ship fluxes, and was selected as an indicator of ship traffic emission in Shanghai Port. The estimated primary PM2.5contribution from ship traffic ranged from0.63to3.58μg m-3, with an average of1.96μg m-3. This PM2.5fraction accounted for4.23%of the total PM2.5in an average level, and reached to a maximum of12.78%. Moreover, there could be about64%of primary PM2.5contributed by ships in Shanghai Port transported to inland region, which caused a non-negligible regional air quality impact. Furthermore, the primary emissions from ship traffic could be transformed into secondary aerosols such as sulfate, nitrate and ammonium through the chemical reaction process in atmosphere, which would have a potential negative effect on atmospheric visibility.