| With the expansion of city scale,the acceleration of industrialization and the increasing number of cars,people's living standards have been improving,the concentration of suspended particulate matter in large and medium-sized cities has been on the rise.This change has not only seriously harmed the ecological environment,but also seriously endangered human health.Due to the characteristics of closed or semi-closed environment,poor ventilation effect and heavy traffic flow,the problem of particulate matter pollution in the underground garage is more serious.Most underground garages adopt natural ventilation,but the ventilation effect is not ideal.A small part adopts mechanical ventilation,but because the staff often consider economic factors,so the mechanical ventilation equipment is basically not open all year round.Very few of them use induced ventilation,but the technology is not mature,so it is not widely used.The ventilation and dilution operation of the existing underground garage is not perfect,which causes many environmental problems in the underground garage.To solve this problem,this paper research the spatial and temporal distribution of particles and the removal effect of spray system in parking lots by spray dust removal,which provides a new way to improving garage environment.The particulate matter,temperature and humidity,and the traffic conditions of personnel and vehicles in an indoor garage of a shopping mall in Dalian were measured for two consecutive weeks,and the meteorological parameters of particulate matter during the test in Dalian were investigated.The results indicate that the distribution of vehicles and people shows an obvious m-shaped curve no matter on weekends or weekdays.During the period of personnel activities,the average PM2.5 concentration exceeded the standard by 54.8% and the average PM10 concentration exceeded the standard by 22.2%.The value of PM2.5/ PM10 in the garage is 29% larger than PM2.5/ PM10 in the environment,indicating that the main particulate pollutants in the indoor parking lot are nanometer-sized particles.And humidity has the greatest influence on the concentration of particulate matter in the garage,followed by PM2.5 meteorological parameters and number of vehicles in Dalian.Pearson correlation coefficient of humidity is 0.470 and the partial correlation coefficient is 0.687.In this paper,the spray dust removal technology is applied to the self-designed environmental chamber.PM2.5 particles are discharged into the environmental chamber by a gasoline generator and sprayed into the environmental chamber by 16 nozzles,so as to achieve the spray dust removal.The relationship between dust removal efficiency and spray volume was explored by measuring the change of particle concentration in the environmental chamber in real time and recording the spray working time.The experimental results showed that the dedusting efficiency of spraying for 5 minutes,spraying for 10 minutes and spraying for 15 minutes were 0.0135,0.0146 and 0.0368 respectively.The corresponding spray amounts were 0.2455 L,0.491 L and 0.7365 L,respectively.This article is based on the above content has developed a closed or semi-closed environment oriented to application of dust capture device performance evaluation of ultrafine particle dust online monitoring system,the system platform is not limited to evaluation of spray system,can be applied to the evaluation of effect of closed space dust pollution,at the same time,the paper using the developed software,comparing the calculated results by an example and software to verify the accuracy of the software.The development of software greatly facilitates the calculation and design of effective dust removal. |
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