Spatio-Temporal Characteristics and Analysis of Atmospheric Environmental Quality in Hainan Island from 2015 to 2021

The unique geographical features of Hainan Island result in spatial and temporal differences in atmospheric Aerosol Optical Depth (AOD) that not only exhibit oceanic characteristics but are also significantly influenced by land sources. As for the above characteristics of the study area, MOD04_3K AOD data from 2015 to 2021 were selected, and linear trend analysis was utilized to explore and analyze the overall spatial distribution pattern and trend of the atmospheric environment in Hainan Island. The AQI data of PM2.5, PM10, O3, NO2, SO2, and CO, provided by ground air quality monitoring stations, were used to probe the spatial and temporal distribution characteristics of the near-surface atmospheric environment. A correlation analysis method and the Apriori algorithm were used to study the correlation between AOD and AQIs. The key findings are as follows: (1) The overall atmospheric environment in Hainan Island showed a decreasing trend from 2015 to 2021; (2) The period of relatively high AOD in Hainan Island occurred during the peak tourist season from November to April of the following year; (3) The AQI values of PM2.5, PM10, NO2, and SO2 demonstrated a decreasing trend, while the AQI value of O3 showed the opposite trend in some local areas; (4) The correlation values between AOD and PM2.5, PM10, and NO2 were higher than those between AOD and SO2, O3, and there was no significant correlation between AOD and CO; (5) The mining results of association rule displayed that the association between AOD and AQI index was closest in Wuzhishan area, followed by Sanya area, and the association between AOD and AQI index was lowest in Wuzhishan area. The results provide credible scientific data and theoretical support for atmospheric pollution monitoring and joint prevention and control in the region.