Abstract：Chemical components in PM2.5 and related optical parameters together with gaseous pollutants were simultaneously monitored during the World Car Free Day in Hangzhou to evaluate the influence of vehicle emissions on fine particle pollution and visibility. Concentrations of NO2, NOx, CO and PM2.5 were 45.0, 50.8, 1119 and 85.8μg/m3 during control period with decrease of 17.5%, 23.3%, 20.6% and 32.6%, respectively, compared with the non-control period. Concentrations of OC, EC and secondary inorganic ions in PM2.5 were 8.58, 4.29 and 25.95μg/m3 during control period, with corresponding decrease of 17.5%, 23.3%, 20.6% and 32.6%, respectively. While the species above increased to 20.24, 10.85 and 27.39μg/m3 after the lifting of control measures, which increased by 136.0%, 152.7% and 5.5%, respectively. Higher NO3-/PM2.5 and NOR ratios were observed during the control period, indicating PM2.5 was more dominated by secondary inorganic transformation. While the contribution of OC and EC to PM2.5 gradually dominated after control with the lower NOR (0.07), suggesting that PM2.5 was mainly derived from carbonaceous aerosol emitted via vehicle emissions. Sulfates, nitrates, organic aerosol, and EC were the major extinction components and they could explain approximately 74.0%~89.7% of total extinction coefficient. The total extinction coefficient increased 60.5% to an extreme value of 438.7Mm-1 after the control period with 26.6% and 24.6% of the light extinction attributed to organic aerosol and EC, respectively. This study highlighted that vehicle emissions had a significant influence on fine particle pollution and visibility impairment in Hangzhou.
徐昶, 沈建东, 何曦, 杨乐, 叶贤满, 洪盛茂, 焦荔. 杭州无车日大气细颗粒物化学组成形成机制及光学特性[J]. 中国环境科学, 2013, 33(3): 392-401.
XU Chang, SHEN Jian-Dong, HE Xi, YANG Le, YE Xian-Man, HONG Sheng-Mao, JIAO Li. Chemical composition, formation mechanism and optical properties of atmospheric fine particles during the World Car Free Day in Hangzhou. CHINA ENVIRONMENTAL SCIENCECE, 2013, 33(3): 392-401.
