本研究确定了某激光粉尘仪测试上海市环境大气颗粒物(PM10和PM2.5)的质量浓度转换系数K值。利用激光粉尘仪和TEOM RP 1400a型监测仪,同时对选定的环境监测站同一监测点的环境大气颗粒物(PM10和PM2.5)进行了测定,得出了该激光粉尘仪测试上海市环境大气颗粒物(PM10和PM2.5)的质量浓度转换系数K值呈基本正态分布,分别为0.00594和0.00158。
The effects of different human walking patterns on contaminant dispersion in residential kitchens were investigated through computational fluid dynamics simulation with the dynamic mesh method.A tracer gas experiment was performed to verify the feasibility and accuracy of the simulation method.Flow characteristics induced by human walking were minutely described,and the transient capture efficiency of the range hood was adopted to assess the impact of human walking quantitatively.Human walking parallel to a counter,human walking parallel to a counter manned by another human,and human walking toward a counter were studied.Results showed that the mutual effect of the wake and thermal plume caused contaminant dispersion and decreased the performance of the range hood as the human subject walked beside the counter.Even a standing person operated ahead the counter,the wake would affect the thermal plume in a certain extent.The decrement of capture efficiency approached 0.5 in the most unfavorable situation.Moreover,the coaction of the positive/negative pressure zone and impinging air jet drew the thermal plume to the human body.The fluctuation of capture efficiency in this condition was moderate relative to that for the human walking pattern beside the counter.This research could provide a comprehensive overview of different human walking patterns and their impact on residential kitchens and thereby facilitate the maintenance of kitchen air quality.
