Real-time correction of light dilution effect for ship emission monitoring of SO₂

With the rapid development of the shipping industry, ship emissions have become a focal point in environmental protection. SO 2 , as a major component of ship emissions, is crucial to monitor to ensure environmental compliance. SO 2 -sensitive ultraviolet (UV) cameras represent an advanced emerging technology for remote sensing monitoring of ship emissions. However, as monitoring distance increases, errors in the monitoring results due to the light dilution (LD) effect rise significantly. The aim of this study is to address the LD effect in SO 2 monitoring for mobile pollution sources and propose a real-time correction method. Based on the atmospheric radiative transfer model and developed data processing algorithms, the method corrects the LD effect in real-time, enhancing the accuracy and reliability of SO 2 UV camera monitoring. Experimental data collected from ship emissions at Yantai port are used to validate the accuracy of the correction method. Results show that the LD effect can lead to a 60% underestimation in the monitoring results at a distance of 4 km. The proposed method effectively corrects the LD effect, improves the accuracy of the monitoring results, lays the foundation for the engineering application of UV cameras in ship exhaust monitoring, and therefore promotes the wide application of UV cameras in air quality monitoring and environmental protection.