## 1 Introduction  
In recent years, with the gradual strengthening of motor vehicle pollution control, the emission sharing rate of ship exhaust pollutants has gradually increased, so the government and researchers have begun to pay attention to the issue of ship pollution control [1]. China is rich in inland shipping resources. In 2018, the freight volume of the Yangtze River trunk line reached 2.69 billion tons, a year-on-year increase of 7.6%, ranking first in the world's inland rivers. At the same time, the annual container throughput of the Yangtze River trunk line reached 17.5 million TEU (20 feet in length), 6.1% [2]. In the last few years, with the gradual strengthening of motor vehicle pollution control, the emission sharing rate of ship exhaust pollutants has gradually increased, so the government and researchers have begun to pay attention to the issue of ship air pollution control. Ships generally use diesel engines as power sources. The diesel engines have poor operating conditions, harsh working environments and high power, and the quality of the marine fuel or diesel used is difficult to guarantee. In addition, the emission standards of ships in my country are seriously behind the emission standards of motor vehicles, and most ships are neglected in maintenance. Therefore, the impact of air pollutants emitted by a single ship on the environment is generally far more serious than that of motor vehicles. Marine diesel engines produce a large number of air pollutants during operation, mainly including CO, CO\({}_{2}\), NO\({}_{X}\), SO\({}_{X}\), HC, particulate matter PM\({}_{2.5}\), VOC\({}_{5}\) (volatile organic compounds), and BC (black carbon) [3]. The SO\({}_{2}\) and NO\({}_{X}\) produced by ship emissions undergo chemical reactions again in the atmosphere to generate pollutants such as sulfate and nitrate [4]. The growing inland shipping has seriously affected the environment near ports and waterways and the air quality of cities and has brought enormous pressure to the prevention and control of atmospheric pollution. With the gradual expansion of the shipping trade and the control of sulfur content in fuel oil, the characteristics of air pollution emissions from ships have changed significantly. Air pollution emissions from ships have attracted more and more attention from the public sector and scientific researchers [5]. In the past ten years, the government and relevant environmental protection departments have formulated and implemented a series of regulatory control measures for the emission of air pollutants from motor vehicles in the region. In contrast, the research on air pollution emissions from ships in inland waters is still relatively weak. The atmospheric pollutants and greenhouse gases emitted by ships will have a great impact on the air quality of the cities around the port and the physical and mental health of the residents. With the promulgation of the country's new air quality standards and the pressure to reduce air pollution from the regional environment, in order to promote the low-carbon, green and sustainable development of the region, it is urgent to conduct comprehensive research and control on regional ship air pollution emissions. In view of this, the GB3552-2018 \"Ship Water Pollution Discharge Control Standard\" issued by the Ministry of Environmental Protection and the General Administration of Quality Supervision and Quarantine of the People's Republic of China has been implemented since 1 July 2018 [6]. The main purpose is to prevent and control water pollution and promote the green development of the manufacturing industry of ships and related devices. The Outline of the Construction Planning of the Chengdu-Chongqing Economic Circle clearly pointed out that the concept of ecological civilization should be fully implemented, the ecological protection of the upper reaches of the Yangtze River should be strengthened, and the red line of ecological protection should be strictly observed [7].