Impacts of different sampling fibers on the determination of the acidity of atmospheric particulates
不同采样膜对大气颗粒物酸性测定影响的研究

Evidence has been obtained that aerosols (especially acid aerosols) have adverse effects on respiratory system of human beings. Moreover, acid aerosols can accelerate the formation of high concentration of secondary aerosol components, affecting environment and climate. This work was aimed at evaluating the impact of different sampling membranes on the acidity determination. Based on standard method of U.S. Environmental Protection Agency for the determination of the strong acidity of fine particulates, different membranes, including quartz, glass, Teflon and mixed cellulose ester (MCE) filter fibers, were dropped with strong acid and extracted by KCl-HClO4-ethanol mixed solution for pH determination. The accuracy and precision of H+ determination with different membranes were estimated. In addition, the calibration curve between H+ added and H+ extracted concentrations for different measurement batches with different kinds of membranes were acquired. Result showed that the precision and accuracy for H+ determination extracted by Teflon, MCE, quartz and glass fiber filters were 9.4% and 7.8%, 9.9% and 13.0%, 15.6% and 18.1%, and 17.8% and 16.1%, respectively. It was noted that the slopes of calibration curve varied greatly on glass membranes (from 0.745 to 1.048 in different batches). Background basic matrix was the highest on glass membrane, and the potential determination error of H+ was the most notable on glass membrane among the four types of membranes detected.