[Pollution characteristics of n-alkanes in atmospheric fine particles during Spring Festival of 2007 in Beijing].

Research PM2.5 aerosols had been carried out with sampler of high-volume sampler during Spring Festival of 2007 in Beijing, and the concentrations of n-alkane in PM2.5 samples were determined via GC-MS. The average concentrations of PM2.5 which were all exceeded WHO threshold values were higher in the night than those in the day time. The n-alkane homolog from C10 to C33 were detected with the major peak carbon numbers ranging from 23 to 25. The total concentrations of n-alkane were higher in the night (943.5 ng x m(-3)) than those in the day time (581.1 ng x m(-3)). And also we found that the average concentrations of n-allkane before New Year's Eve (1,025.5 ng x m(-3)) were higher than those after (536.6 ng x m(-3)). The CPI values were 0.9-1.4 with average of 1.15. Those results may mean that primary resource of n-alkane in fine particles was the incomplete combustion of fossil fuel. The percent contribution of leaf "Wax" n-alkane indicated that about 8.5%-47% of n-alkane came from waxy leaf surface abrasion.