Markers of East Asian dust storms in March 2010

The variations in particulate matter (PM) and in eighteen metallic elements in four different particle sizes in the air of southern Taiwan were investigated from February to March 2010. The variation in mean mass concentrations of PM_2.5, PM_2.5-10, PM₁₀, and TSP between Asian dust storm (ADS) and non-dust storm (NDS) periods suggested that the dominant fractions were PM_2.5-10 and PM_2.5, respectively. The obvious differences in metallic element concentrations between ADS and NDS periods suggested that crustal elements (Fe, Mg, Sr, Co, Ba and Mn) can be used as dust storm indicators, in addition to Ca and Al. Both mass fractions and metallic concentration ratios indicated that the PM_2.5-10 fraction can distinguish between ADS and NDS periods. An enrichment factor (EF_c) demonstrated that most anthropogenic elements were significantly lower in ADS periods than in NDS periods. The EF_c values for anthropogenic elements in coarse particles may be used as indicators of dust storm invasion as well. An association was found between the extent of dust storm effects on receptors and the residence time (duration) of the event, in addition to the transport pathway.