基于隧道法的机动车PM2.5排放因子研究

选取典型城市隧道进行机动车排放因子测试,在南京市富贵山隧道进行监测,对隧道内的PM_2.5浓度、风速风向、交通量、车型、速度及气象条件进行采集分析、计数、分类、观察。建立守恒方程和多元线性回归求解PM_2.5平均排放因子,分别得出出租车（天然气）、小汽车、公交车（天然气）、大客车（柴油）、大货车在35⁴0 km·h-1,40⁴5 km·h-1,45⁵0 km·h-1范围内的平均排放因子;其中最大值为0.157 2 g·（km·辆）-1,最小值为0.015 21 g·（km·辆）-1,在相同速度范围内城市大货车的PM_2.5的平均排放因子明显高于其它,其次是大客车（柴油）、公交车（天然气）、小汽车、出租车（天然气）。     

Electron spin resonance analyse on the production of hydroxyl radicals by ozone photolysis

AbstractIn order to explore the production of hydroxyl radical(·OH)in a confined space,a novel ozone-light irradiation system is constructed in this study,and the·OH radical is measured by spin-trapping electron spin resonance(ESR)method in which 5,5-dimethyl-1-pyrroline-N-oxide(DMPO)is selected as the spin-trap.Several influence factors including the light intensity,the irradiation time and DMPO mass concentration are discussed. The results show that in this experimental system,with DMPO mass concentration of 1g/L and the irradiation time of 30 min,the·OH radical can be best captured.Besides,both wavelength and intensity of the irradiation light could effect the generation of·OH radical.These results are of great importance to further study the sterilization effect of·OH radical in confined space.