Characterization of Personal PM_(2.5) Carbonaceous Fraction Exposure of Children, Tianjin

摘要

Particulate matter has already been the primary pollutant of most cities in China. Among PM, PM_(2.5) has a closer relationship with human (especially the elderly, children and other vulnerable population) health effect. Considering the exposure error using ambient PM_(2.5) data as surrogate, personal PM_(2.5) sampling was likely to evaluate the characterization of personal exposure precisely. In this study, 36 children in Tianjin were volunteered to collect personal PM_(2.5) exposure samples during non-heating period and heating period in 2010. Carbonaceous fraction of samples was analyzed and potential sources of carbonaceous composition were described. The average concentrations of organic carbon (OC) and element carbon (EC) were 29.16±12.62 and 3.25±1.70 μg/m~3 in non-heating period, 37.56+18.48 and 8.73±4.13 μg/m~3 in heating period. The concentration of secondary organic carbon (SOC) was calculated to be 20.20 and 26.47 μg/m3, which accounted for 68% and 70% of OC during two monitoring periods. Weak correlations between OC and EC were obtained in both periods, and the ratio of OC and EC (OC/EC) distributed in the range of 2.3-16.0, with the average values of 9.6 and 5.2 in the two periods, respectively. Thus, OC and EC of personal PM_(2.5) exposure were derived from different sources. The average concentrations of OC1, OC2, OC3, OC4, EC1 and EC2 in the non-heating season and heating season were 8.49, 5.66, 7.44, 3.59, 6.75, 0.47μg/m~3 and 5.56, 7.99, 11.44, 7.65, 13.36, 0.25 μg/m~3, respectively. The significant difference (p＜0.05) of OC1 was found between the two monitoring periods, which was influenced by the biomass burning in Tianjin. The characteristic ratio of PAHs showed that coal burning and vehicle emission were the main sources of personal PM_(2.5) exposure.