The outbreak of the COVID-19 epidemic has led to great changes in the world economy and environment . Therefore , it is crucial to assess the variations in shipping activities and pollution emissions caused by the COVID-19 epidemic . This study made an attempt to investigate the effects of COVID-19 pandemic on the merchant ship activity and the resulting atmospheric pollutant emissions in Shanghai port waters . By comparing the AIS data in February 2019 and in February 2020 , it can be found that the count and utilization frequency of merchant ships including cargo ships , container ships and tankers are reduced during the epidemic period . Furthermore , the reduced utilization frequency is found to vary with different ship sizes for each merchant ship type . In addition , it is found that the COVID-19 pandemic resulted in longer ship turnaround time that might be caused by more operation time required for completing the berthing and anchoring activities during the epidemic period .