Chemical characteristics of carbonaceous aerosols during dust storms over Xi'an in China

Characterization of carbonaceous aerosols including CC (carbonate carbon), OC (organic carbon), and EC (elemental carbon) were investigated at Xi'an, China, near Asian dust source regions in spring 2002. OC varied between 8.2 and 63.7 ?gg m -3, while EC ranged between 2.4 and 17.2 ?g m -3 during the observation period. OC variations followed a similar pattern to EC and the correlation coefficient between OC and EC is 0.89 (n = 31). The average percentage of total carbon (TC, sum of CC, OC, and EC) in PM 2.5 during dust storm (DS) events was 13.6%, which is lower than that during non-dust storm (NDS) periods (22.7%). CC, OC, and EC accounted for 12.9%, 70.7%, and 16.4% of TC during DS events, respectively. The average ratio of OC/EC was 5.0 in DS events and 3.3 in NDS periods. The OC-EC correlation (RDepartment of Civil and Environmental Engineerin