This distribution of seasonal Black Carbon loadings at Tongyu, namely low in summer and high in spring, autumn, or winter as a result of coal combustion and biomass burning emissions [Streets et al., 2001], is similar to the state of other Asian sites (Table 2). The weather conditions like wind speed etc. are important factors to control the seasonal variation of Black Carbon level, especially wet deposition of precipitation to aerosol particles in summer at Tongyu (Figure 2).