Spatiotemporal Pattern Of Aqi In Shandong, China Using The Empirical Orthogonal Function Analysis

Daily AQI mass concentration measurements at 91 stations over a 4-year period from January 1, 2014 to December 31, 2017 were collected in Shandong province. EOF analysis was used to obtain spatial and temporal patterns of AQI based on weekly average data. The first three modes of weekly average AQI explained 82.33% of the total variance. With the highest variance contribution and the large amplitude change of time coefficient, the first mode showed high AQI in the cities bordering neighboring provinces in western Shandong and the regions with more mountains in central Shandong. The second mode showed the opposite trend of AQI in eastern compared with western, and the third mode reflected the opposite trend in southern compared with northern in Shandong province. The results showed the high AQI mainly occurred in winter and its early and late periods, the number of days with high AQI has being gradually decreasing.