Study On Dust Emission Characteristics Of Typical Construction Site In Chong Qing

With the rapid development of society and economy,in recent years,"Beijing-Tianjin-Hebei","Yangtze River Delta","Pearl River Delta" and Chengdu-Chongqing urban agglomeration,have burst into more serious haze weather.Air pollution has become one of the most prominent environmental problems in China's cities.With the deepening of the urbanization process,a large number of construction sites have become an important source of atmospheric particulate matter,Chongqing City is no exception;However,researches on the characteristics of dust emission in Chongqing is relatively scarce,especially the research on emission factors.In this study,based on the typical construction site of Chongqing-the construction site of Chongqing environmental protection industrial park in Lijiang of Liangjiang New Area,dust emission characteristics and pollution levels are systematically researched in the three different construction stages-earthwork excavation,foundation construction,general construction and earth backfill,so as to provide scientific basis and technical support for the relevant government management departments to formulate dust control measures.Firstly,the dust concentration and meteorological parameters of each stage are continuously monitored,and the evolution of the dust concentration of the building is analyzed with time.The factors influencing the dust concentration of the building are discussed.Secondly,the initial emission factors of different construction stages are established by using flux calculation method.The dust emission factors of different construction stages are obtained by model calibration method.The samples of PM₁₀ and PM_2.5filters were collected at different construction stages,and the elements were analyzed by elemental analysis,water-soluble ionic components and OC/EC components.The corresponding chemical composition characteristics were obtained,And the chemical components of PM₁₀ and PM_2.5 were compared and analyzed.The results are as follows:?1?During the foundation excavation stage,the net emission concentration of buildings is mainly from 12:00 to midnight.During the foundation construction stage,the net emissions of buildings are mainly concentrated from 8:00 am to 23:00 pm.The general construction and earth-Dust net emissions are mainly concentrated from 8 am to 18 pm.The net concentrationof building dust is obviously affected by meteorological conditions,as it is positively correlated with wind speed and relative humidity and weakly correlated with temperature.?2?The construction dust emission factor for different construction stages is 0.25g/?m2.h?for excavation stage,0.09 g /?m2.h?for foundation construction and 0.07 g /?m2.h?)for general construction and earth backfill.?3?The content of Ca2 +,Na +,SO42-and NO3-in the water-soluble ionic component is higher than that in the other aspects,and the content of Si,S,Ca,Fe and Zn is higher in the general construction and earth-,And the net content of SO42-is the highest in the foundation excavation stage.The net content of Ca2 + in the general construction and earthfill phase is the highest.?4?The average ratio of PM_2.5/PM₁₀ was 0.496 in the foundation excavation stage.The average ratio of PM_2.5/PM₁₀ was 0.595 in the foundation construction stage.In the general construction stage and earthfill phase,PM_2.5/PM₁₀ The ratio is 0.661.