Atmospheric Emission Inventory Of Air Pollutants From Ships And Heavy Metals Health Risk Assessment For Population In Xiamen Port

With the increase in shipping,atmospheric pollutants emitted by ships have become one of the main sources of pollution in the port,which has seriously affected the local air quality and the population health.Therefore,it was particularly important to carry out the assessment and prediction of air pollutants emissions from ships and the health risk assessment of port population.This study established the air pollutants emission inventory of ships at Xiamen Port,and estimated the heavy metals emission inventory of airborne particulates from ships from 2020 to 2025.Combined with the health risk assessment of heavy metals in atmospheric particulate matter at the port,this study comprehensively evaluated the emission reduction effects and health benefits of ship emission control.Based on the high-resolution Automatic Identification System data,this study established the ship emission inventory of Xiamen Port in 2020,in which the total emissions of 7 kinds of pollutants NOx,SO2,CO,VOCs,HC,PM10 and PM2.5 were 35955,8858,3186,1396,1427,1016 and 880 ton.Affected by the 2020 Spring Festival holiday and Corona Virus Disease,the monthly emissions of pollutants were the lowest in February and the highest in August.Other ships,container ships,cargo ships and passenger ships were the main emission contributors.Specifically,ships at berth contributed to a major emissions of pollutants because of the longest berthing time,and pollutants from the main engine and auxiliary engine had the highest sharing rates of emissions.From the perspective of the spatial distribution of ship air pollution,ship emissions were mainly concentrated on the coastline and main shipping routes of Dongdu Port and Haicang Port.In addition,we forecasted the ship emission inventory of Xiamen Port from 2021 to 2025,and set a ship emission control scenario for reducing the sulfur content of fuel and increasing the utilization rate of shore power in 2025.From the perspective of the total emission reduction of 7 kinds of pollutants,the emission reduction effect of shore power utilization rate of more 50%was better than that of reducing the sulfur content of marine oil from 0.5%to 0.1%.However,when the sulfur content of fuel was reduced to 0.1%,the emission control of PM and SO2 showed a better reduction effect.In this study,PM2.5 samples from July to September,November and December were collected simultaneously at Haitian Wharf and Songyu Wharf in Xiamen Port,and metal elements analysis was performed.The results of elements in the atmospheric PM2.5 at the sampling points showed that the concentrations of Na,Mg,Al,K,Ca and Fe elements were high(92-97%),which accounted for a relatively low abundance of trace elements.The change of metal V and Ni concentration was related to the wind direction in different seasons,and was higher when the westerly and southern wind prevailed.The concentration of V and Ni in summer(July to September)was higher than that in autumn and winter(November,December),and the ratio of V/Ni also showed the same pattern,indicating that the influence of ship sources caused by the prevailing southwesterly wind in summer on sampling locations was greater than the northeasterly wind in autumn and winter.The contribution rate of ship sources was determined by Positive Matrix Factorization.The contributions of ship sources to the mass concentration of PM2.5 in Haitian Wharf and Songyu Wharf were 7.7%and 7.1%.The respiratory health risk of heavy metals from different pollutions source categories in 2020 was assessed by the risk assessment guidelines of the United States Environmental Protection Agency.The non-carcinogenic risk of heavy metals could be ignored,however,the total carcinogenic risk of heavy metals to children and adults was 6.81×10-6 and 2.72×10-5,indicating a existence of potential carcinogenic risk.61.8%of higher carcinogenic risk of V came from ship emissions,and the carcinogenic risk caused by ship emissions contributed 17.6%to the total carcinogenic risk.This research estimated and predicted the heavy metal emission inventory of ships from 2020 to 2025.In 2025,we compared emission reduction policies of reducing the sulfur content of fuel oil with increasing the utilization rate of shore power on the emission reduction effect of heavy metals,and found that contribution by reducing the sulfur content of fuel oil would be more significant than that by increasing the use of shore power.By carrying out heavy metal health risk assessment of the ship emission reduction scenario in 2025,we found that the non-carcinogenic risk of heavy metals could be ignored.In the case of ship emission reduction,the total carcinogenic risk value of adults was higher than 1×10-6,and would cause a carcinogenic risk.When the sulphur content of the ship’s fuel oil was 0.5%,the total carcinogenic risk value of children was higher than 1×10-6,and there was a risk of carcinogenesis.When the sulphur content of the ship’s fuel oil was reduced to 0.1%,the total carcinogenic risk value of children was below 1×10-6,and the risk of cancer could be negligible.On the basis of using 0.1%sulphur content of fuel oil,the carcinogenic risk of children and adults could been reduced simultaneously with the increases in shore power usage,while metal V would still has a carcinogenic risk for adults under the ship’s emission reduction measures.