Regulations for the control of air-pollutant emissions from ships within pollutant emission control areas (ECAs) have been issued for several years, but the lack of practical technologies and fundamental theory in the implementation process remains a challenge. In this study, we designed a model to calculate the nitrogen-oxide-emission intensity of ships and the sulfur content of ship fuels using theoretical deduction from the law of the conservation of mass. The reliability and availability of the derived results were empirically evaluated using measurement data for NO_x, SO_2, and CO₂ in the exhaust gas of a demonstration ship in practice. By examining the model and the measured or registered fuel-oil-consumption rates of ships, a compliance-determination workflow for NO_x-emission intensity and fuel-sulfur-content monitoring and supervision in on-voyage ships were proposed. The results showed that the ship fuel’s NOx-emission intensity and sulfur content can be evaluated by monitoring the exhaust-gas composition online and used to assist in maritime monitoring and the supervision of pollutant emissions from ships. It is recommended that uncertainties regarding sulfur content should be considered within 15% during monitoring and supervision. The established model and workflow can assist in maritime monitoring. Meanwhile, all related governments and industry-management departments are advised to actively lead the development of monitoring and supervision technology for ship-air-pollutant control in ECAs, as well as strengthening the quality management of ships’ static data.

Paeonia rockii has been a traditional medicinal material from time immemorial. It is an important plant resource of ethnic medicine and chinese herbal medicine. It has unique effects on heat and cool blood, promoting blood circulation and dispersing blood stasis, analgesia and promoting menstruational flow. It is also a first-class protected plant. With the increasing demand for the bark and roots of P. rockii in China’s medicinal market, the continuous high-intensity and disorderly excavation has led to a sharp decline in wild resources. P. rockii is in imminent danger and needs to be saved and protected urgently. In this study, the distribution records of P. rockii in China, combined with environmental factors, are used to simulate the current potential distribution area of P. rockii through MaxEnt model. The environmental factors affecting the distribution of P. rockii are obtained by using the contribution rate of environmental factors and a jackknife test analysis, and the appropriate value of environmental factors is determined by using the response curve. The results show that the AUC value of test set data is 0.985 and that of training set data is 0.987. The prediction accuracy of the Maxent model is extremely high and the simulation effect is very good. At present, the high suitable areas of P. rockii are mainly distributed in the shape of cake in Southern Ningxia, southern Gansu and southern Shanxi, accounting for 15.58% of the total suitable areas. The most important environmental factor affecting the geographical distribution of P. rockii is the altitude; Under the future climate change scenario, the total suitable area of P. rockii shows a decreasing trend, among which the area of high suitable area shows an obvious decreasing trend, the mass center of high suitable area of P. rockii generally tends to migrate to the northwest, and the migration range is large under the scenario of high concentration emission. The research results can provide scientific data support for P. rockii to to cope with the changes in suitable areas caused by climate change and the establishment of effective protection, clarify the change and heterogeneity of P. rockii in different regions of China in the future, and clarify its ecological needs, which has certain practical significance.

On March 11, 2011, a serious radionuclide leakage accident occurred at Fukushima Daiichi nuclear power plant, and a large number of radionuclides were released, causing serious pollution to the ocean environment. On August 25, 2021, Japan announced the overall plan for the discharge of radioactive sewage from the Fukushima Daiichi nuclear power plant into the ocean, and the discharge will begin around the spring of 2023. All operational and under-construction nuclear power plants in China are distributed in coastal areas presently. In case of a nuclear leakage accident, radionuclides will diffuse through the ocean and pollute the ecological environment. The study of radionuclide diffusion mechanism in the ocean and emergency response plays an important role in accident mitigation under oceanic radioactive events. A radionuclide diffusion model in the ocean was established and the radionuclide diffusion mechanism in the ocean was analyzed. And then a prediction and monitoring system of radionuclide diffusion in the ocean was proposed. The results show that the short-term radionuclide diffusion is mainly influenced by the source term, flow field and decay of ¹³¹I, and the degree of influence decreases in turn. On the whole, influences of the flow field and ¹³¹I decay are weakened during the long-term diffusion. At the same time, the influence of ¹³⁷Cs decay begins to be obvious and the influence of suspended matter is increasing. The influence of ocean organisms is always small. Problems of scientific prediction and protection were analyzed, and the emergency response scheme was given. It is of great significance to improve the capacity of emergency response for oceanic radioactive events.

With the development of global maritime trade, ship emissions pose an increasing threat to the global atmospheric environment, especially in international navigation waters and important port areas, where their impact on coastal air quality and ecosystems is becoming increasingly significant. This study proposes a high-throughput gridding algorithm (H-Grid) based on spatial hashing to rapidly generate ship emission inventories, which overcomes the inefficiency of traditional methods caused by complex index building and maintenance. The H-Grid algorithm achieves a constant processing time per data point and possesses inherent parallelism. Based on the H-Grid algorithm, taking the Yellow Sea area between China and Republic of Korea as a case study, the emissions of atmospheric pollutants from ships in 2024 were calculated, and their spatiotemporal distribution characteristics were analyzed. In our empirical study, the algorithm’s computational efficiency for processing millions of AIS records was improved by over 10 times compared to traditional geometric calculations, and by more than 4 times when compared to mainstream database spatial queries. Our findings provide an efficient tool for large-scale maritime emission analysis, strongly supporting the green development of global shipping.

Study on calculation model and risk area of radionuclide diffusion in coastal waters under nuclear leakage accidents with different levels can help predict and evaluate consequences of radionuclide leakage accidents. Thus they play an important role in emergency response and accident mitigation. In the first step of the study, a climate hydrodynamic model in China coastal waters was established based on the climate data. In the next step, according to the real-time meteorological data, a hydrodynamic model in coastal waters of Haiyang nuclear power station was founded using the result of the climate hydrodynamic as a boundary. Then, according to the result of the hydrodynamic model in coastal waters of Haiyang nuclear power station, a radionuclide diffusion model in coastal waters of Haiyang nuclear power station was set up, in which the Euler method was adopted. With the radionuclide diffusion model, the total leaked radioactivity of radionuclides was set from 10¹⁸Bq to 10¹²Bq with a decrease of every two orders of magnitude. Thus, scenarios of radionuclide diffusion under assumed nuclear leakage accidents with different levels were calculated and their corresponding risk area were analyzed under the assumption that radionuclides leaked for consecutive five days. The results show that when the leaked radioactivity of radionuclides is 10¹⁸Bq, the risk area on the seventh day is about 41 km east, 22 km south and 19 km west of the power station; on the fourteenth day, the risk area is about 65 km east, 22 km south and 25 km west of the power station. When the total leaked radioactivity of radionuclides declines by two orders of magnitude, the risk area will be reduced by about 10 km–20 km in the east direction accordingly. When it declines to 10¹⁴Bq, the risk area decreases sharply to a small area. When it declines to 10¹²Bq, the risk area is barely found. This model was verified from two aspects, namely the flow field and the radionuclide concentration. Hydrodynamic results can well describe the Yellow Sea cold water mass, Yellow Sea warm current and tidal current. Changes of radioactivity in different positions are fundamentally consistent with that in Fuikushima nuclear leakage accident. It indicates the hydrodynamic model and radionuclide diffusion model in the study are feasible and reliable.