Factors Influencing the Concentration of Negative Air Ions in Urban Forests of the Zhuyu Bay Scenic Area in Yangzhou, China

Negative air ions (NAIs) are an important indicator of air cleanliness in an area, and play a vital role in promoting the psychological and physiological functions of the human body. However, there are few studies regarding the relationship between NAI concentration and various environmental factors in urban forests. Therefore, we established an observation point in the Zhuyu Bay Scenic Area in Yangzhou City and continuously measured concentration changes in NAIs for three years. At the same time, we also monitored 14 meteorological factors. A random forest model was used to determine the important environmental factors that affected changes in negative air ion concentrations from a non-comprehensive perspective, determine the prediction accuracy of the model, and screen out environmental factors that have a significant impact on negative air ions. The results showed that the environmental factor that NAIs were the most sensitive to in the Zhuyu Bay urban forest was humidity, followed by PM2.5, then wind direction, methane gas, and finally, temperature. Humidity was the most critical factor primarily because it directly affects the formation of NAIs in the environment and vegetation. We used big data to analyze the relationship between NAIs and environmental factors in forest parks. The results help deepen our understanding of NAIs characteristics and their application in urban forests.