## 4 Calculation of Air Pollutant Emissions from Ships
### Uncertainty Analysis of Emissions Calculation  
In the process of calculating air pollution emissions from ships, due to the influence of data collection and sorting, uncertainty inevitably exists, but the uncertainty can be analyzed and studied to make the calculation results as close to the real value as possible. Based on AIS data, this paper uses the power method to calculate and analyze the air pollution emissions from ships in the main urban area of Chongqing from September to \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Condition** & **CO** & **HC** & \(\mathbf{NO_{X}}\) & \(\mathbf{PM_{10}}\) & \(\mathbf{PM_{2.5}}\) & \(\mathbf{SO_{X}}\) & \(\mathbf{CO_{2}}\) \\ \hline Main & 27.52 & 12.51 & 263.41 & 6.38 & 5.10 & 11.51 & 16,165.09 \\ Main & 35.68 & 16.22 & 341.49 & 9.81 & 6.62 & 14.92 & 20,956.93 \\ Main engine motorization & 1.39 & 0.70 & 8.30 & 0.23 & 0.18 & 0.37 & 521.86 \\ Auxiliary & 0.68 & 0.30 & 5.81 & 0.19 & 0.15 & 0.37 & 520.62 \\ Auxiliary & 1.78 & 0.79 & 15.27 & 0.51 & 0.40 & 0.97 & 1368.67 \\ Auxiliary & 0.13 & 0.06 & 1.11 & 0.04 & 0.03 & 0.07 & 99.52 \\ Auxiliary & 27.85 & 12.38 & 238.49 & 7.89 & 6.31 & 15.22 & 21,370.28 \\ engine mooring & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Air pollutant emissions of main and auxiliary engines under different navigation conditions (unit: t). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Condition** & **CO** & **HC** & \(\mathbf{NO_{X}}\) & \(\mathbf{PM_{10}}\) & \(\mathbf{PM_{2.5}}\) & \(\mathbf{SO_{X}}\) & \(\mathbf{CO_{2}}\) \\ \hline Main & 28.96 & 29.12 & 30.14 & 25.47 & 27.15 & 26.49 & 26.50 \\ Main & 37.54 & 37.75 & 39.08 & 39.17 & 35.18 & 34.35 & 34.35 \\ engine motorization & 1.47 & 1.64 & 0.95 & 0.91 & 0.97 & 0.86 & 0.86 \\ Auxiliary & 0.71 & 0.70 & 0.66 & 0.77 & 0.82 & 0.85 & 0.85 \\ Engine cruise & 1.88 & 1.85 & 1.75 & 2.02 & 2.15 & 2.24 & 2.25 \\ Auxiliary & 0.14 & 0.13 & 0.13 & 0.15 & 0.16 & 0.17 & 0.16 \\ engine motorization & & & & & & \\ Auxiliary & 29.30 & 28.81 & 27.29 & 31.51 & 33.57 & 35.04 & 35.03 \\ engine mooring & & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Contribution ratio of each pollutant under different navigation conditions (unit: %). December 2021. When calculating AIS ship activity data, there may be some ships in the area without AIS equipment installed, and there may be data collection errors and human errors in the process of collecting AIS data using python code. The uncertainty of this study mainly includes the following four aspects:  
* Ship database. Since there is no ship main and auxiliary engine power in the obtained AIS data, this study used the ship MMSI provided in the AIS information as a key factor to finding the ship's main engine power in the National Maritime Traffic Safety Management Information Service Platform (AIS Information Service Platform). The greater the power of the main engine, the more environmental protection fees need to be paid. For this reason, some shipping companies have transformed the main engine of the ship to make the \"inconsistency\", causing the real main engine power of the ship to be greater than the main engine power in the AIS information service platform. In addition, some ships without main engine power in the AIS information service platform use the recommended main engine power value, which is far from the actual value of the main engine power of the ship. On the other hand, the database of auxiliary engine power is seriously lacking. This study uses the ratio of main and auxiliary engine power to determine the auxiliary engine power based on domestic and foreign research experience. * Emission factor. Emission factors are particularly important in the calculation of emissions inventories. The experimental cost of emission factor measurement is high, and the operation is difficult. At present, there are few experimental measurement results of the emission factor of inland river ships in China, and the authenticity is difficult to guarantee.