# Impact of Disruption on Ship Emissions in Port: Case of Pandemic in Long Beach
## 4 Experiment and Analysis
### Emission Analysis of Different Ship Operating Conditions and Waiting Time  
Interpreting the data according to the various operational conditions while analysing ship emissions in the port area is vital. Using the vessel type in the AIS data, the different operational statuses of the vessels are determined, and the results are split into three categories: ME, AE, and boiler. In terms of CO\({}_{2}\), for example, the analysis of the AIS data indicates that auxiliary engines and boilers emitted approximately 236,965 million tonnes of CO\({}_{2}\) in the POLB region in 2019, while, in 2020, auxiliary engines and boilers emitted approximately 240,536 million tonnes; in 2021, the data soared to approximately 496,012 million tonnes. The doubling of the growth means that the POLB is overcrowded, and there is an urgent need for policies or solutions to reduce emissions from port-wide vessels.  
In terms of the proportion of emissions from different types of vessel engines, the POLB differs slightly from other ports. Emissions from ships within other ports are mainly from MEs, while emissions from the POLB are mainly from AEs and boilers. This is partly due to congestion in the port. Figure 5 illustrates the proportion of emissions from different types of engines for all types of ships.  
As the shore power policy only applies to berthing vessels, for a better analysis of its effectiveness, the operational states of the ships were divided into four categories: transit, manoeuvring, berthing, and anchoring. Figure 6 shows the CO\({}_{2}\) emissions of a ship in different states of motion for all types of ships.  
Figure 4: (a) CO\({}_{2}\) Emissions by ship types at the POLB from 2019 to 2021; (b) NOx Emissions by ship types at the POLB from 2019 to 2021; (c) SOx Emissions by ship types at the POLB from 2019 to 2021; (d) CO Emissions by ship types at the POLB from 2019 to 2021; (e) PM2.5 Emissions by ship types at the POLB from 2019 to 2021; (f) PM10 Emissions by ship types at the POLB from 2019 to 2021.  
Figure 5: (a) Emission proportion of different engine types in 2019; (b) Emission proportion of different engine types in 2020; (c) Emission proportion of different engine types in 2021.  
As can be seen from the graph, the proportion of emissions from ships in the berthing state decreases significantly in 2020 and 2021, due to further improvements in the shore power policy. The implications of the shore power policy are significant. However, the proportion of emissions from ships in the anchoring state rises, which confirms the increased congestion in the POLB.  
Figure 7 depicts many sorts of ships' waiting times. As can be seen from these graphs, ships are waiting longer in the port area due to decreased productivity. The reason for this is the reduction of workers in the port area due to the pandemic. Congestion in the POLB increases year on year over the three-year period of 2019 to 2021.  
Combining Figures 6 and 7, despite the steep increase in congestion in the POLB, emissions from vessels in berthing condition have decreased. This shows the significance of the implementation of the shore power policy.