This paper presents a study on the energy efficiency and emissions of a converted high-revolution bore 79.5 mm/stroke 95 mm engine with a conventional fuel injection system for operation with dual fuel feed: diesel (D) and natural gas (NG). The part of NG energy increase in the dual fuel is related to a significant deterioration in energy efficiency $\left({\eta }_i\right)$ , particularly when engine operation is in low load modes and was determined to be below 40% of maximum continuous rating. The effectiveness of the D injection timing optimisation was established in high engine load modes within the range of a co-combustion ratio of NG $\le$ 0.4: with an increase in ${\eta }_i$ , compared to D, the emissions of ${\mathrm{NO}}_{\mathrm{x}}+$ HC decreased by 15% $\mathrm{to}$ 25%, while those of ${\mathrm{CO}}_2$ decreased by 8% to16%; the six-fold $\mathrm{CO}$ emission increase, up to 6 g/kWh, was unregulated. By referencing the indicated process characteristics of the established NG phase elongation in the expansion stroke, the combustion time increase as well as the associated decrease in the cylinder excess air ratio (α) are possible reasons for the increase in the incomplete combustion product emission.

This review investigates the ship emission measurements using multirotor unmanned aerial vehicles (UAVs). The monitoring of emissions from shipping is a priority globally, because of the necessity to reduce air pollution and greenhouse gas emissions. Moreover, there is widespread global effort to extensively measure vessel fuel sulfur content (FSC). The majority of studies indicate that more commonly used methods for measuring ship emission with UAVs is the sniffing method. Most of the research is concerned with determining the fuel sulfur content. Fuel sulfur content can be determined by the ratio of CO₂ and SO₂ concentration in the exhaust gas plume. For CO₂, the non-dispersive infrared (NDIR) method is used, the most common measuring range reaches 0–2000 ppm, the overall measuring range 0–10,000 ppm, and detection accuracy is ±5–300 ppm. For SO₂, the electrochemical (EC) method is used, the measuring range reaches 0–100 ppm, and the detection accuracy is ±5 ppm. Common UAV characteristics, used in measurement with ships, involve the following: 8–10 m/s of wind resistance, 5–6 kg maximum payload, and a flight distance ranging from 5 to 10 km. This can change in the near future, since a variety of emission measuring devices that can be mounted on UAVs are available on the market. The range of available elements differs from device to device, but available ranges are allowed and the accuracy provides good possibilities for wider research into ship emissions.

Global shipping generates substantial emissions that can adversely affect air quality in port cities, yet the detectability of ship-related pollution by urban monitoring locations remains insufficiently understood. This study aims to identify the meteorological conditions under which ship exhaust plumes can be detected at a stationary air-quality monitoring station located 1.4 km from the Port of Klaipeda. Night-time particulate matter and NO measurements from an AQMesh station were synchronized with Automatic Identification System (AIS) ship-tracking data, and an artificial neural network was applied to determine the environmental parameters most strongly associated with detectable pollution peaks. Kernel Density Estimation (KDE) was used to map the spatial patterns of ship activity by vessel type. The results indicate that plume detection is most likely to be detected with moderate wind speeds (8–12.5 m/s for PM and 7.5–9.6 m/s for NO), elevated humidity (>84%), and higher-pressure ranges for particulate matter. Warmer night-time conditions further enhance pollutant transport by reducing atmospheric stability. KDE analysis shows that potential pollutant accumulation zones differ by vessel type, with the most intense hotspots forming near anchorage locations rather than along transit routes. Overall, the findings demonstrate that ship-related pollution can be detected at distances exceeding 1 km under specific meteorological conditions and highlight the parameters that most strongly govern plume penetration into the urban environment.

The problem of marine litter is one of the most important ecological problems in many countries. Lack of ecological consciousness and disregard for environmental regulations for marine pollution, results in increasing and sometimes even dangerous amounts of floating litter that either pollutes coastal areas or end up degrading into ever smaller particles and poi-soning marine fauna. To solve this problem one of innovative marine litter collection nets – a light weight, easy to assemble was created. However marine litter collection would create additional trawling work which results in additional air pollutant emissions. It is there for necessary to evaluate the air pollutant emissions that occur during trawling of nets and aim to provide tools for ecological optimization of trawling work so that the least amounts of air pollution would be created while gathering the greatest amount marine litter. The special raft was designed and constructed for such nets test. The test was performed in Curonian lagoon. Marine litter collection requires additional energy consumption, because of increase of thug's engines power to overcome increase of nets resistance, that also leads to additional fuel consumptions and higher exhaust gas emissions. The article is based on experimental research of a light weight marine litter collection nets resistance measurement. Evaluation of additional energy consumption and increased exhaust gas emissions during trawling.