Ionic composition of TSP and PM2.5 during dust storms and air pollution episodes at Xi'an, China - Shen, Zhenxing; Cao, Junji; Arimoto, Richard; Han, Zhiwei; Zhang, Renjian; Han, Yuemei; Liu, Suixin; Okuda, Tomoaki; Nakao, Shunsuke; Tanaka, Shigeru (Atmospheric environment (1994), 2009)