In order to explore the reaction mechanism of air pollutants to the strength of tourism activities, the PM2.5 mass concentration data of four automatic air quality monitoring stations in Zhangjiajie, a typical eco-tourism city, during the peak tourist season in 2017 were taken as the research object, and the "weekend effect" of PM2.5 was discussed by eliminating trend fluctuation analysis method. The results show that the daily variation curves of PM2.5 mass concentration in Yongding New District, Dianyeju and Weiyang Road stations are basically the same, showing double peaks, with the peaks appearing at around 13:00 and 22:00 respectively. Compared with them, there are obvious differences in Yuanjiajie station. The PM2.5 mass concentrations at Yongding New District and Dianyeju stations are slightly higher on weekdays than on weekends, while those at Weiyang Road and Yuanjiajie stations are higher on weekends than on weekdays. In order to further explore the inherent law of PM2.5 mass concentration changes, thetrend fluctuation analysis of PM2.5 mass concentration sequences at each stationwas carried out. It is found the PM2.5 mass concentration sequences show significant characteristics of long-term sustainability, and there exists a turning point in the long-term sustainability of urban stations, but there is noturning point at scenic spots.The speculated reason is that the scenic spots are disturbed by tourism activities.
