Study On Calculation And Variation Characteristics Of Subway Pollutant Concentration Based On Passenger Flow

In recent years,with the rapid development of urban rail transit,rail transit passenger flow continues to increase,rail traffic travel accounts for the proportion of public transport is more and more high,people pay more attention to the station air quality is good or bad.However,most of the current research on the air quality of the station focused on the monitoring of the concentration of pollutants in the station and the monitoring of the related microorganisms,and whether it exceed the limits of the relevant norms,But can not describe the variation characteristics of the pollutants in the subway station under various factors.Study on the variation characteristics of pollutants in subway stations have a greater significance for improving the indoor air quality and saving energy.Firstly,according to the current situation of relevant theories and measurements at home and abroad,the physical and mathematical models of the pollutant characteristics of the subway station are established according to the subway station specific situation and the factors influencing the variation of pollutant concentrations are summarized and introduced in detail.and make the CO₂ as research object to analysis and research.Then,according to the actual situation of the subway system,select the station of Chongqing MTR Line 6,monitore the wind speed,passenger flow,train operating parameters,ventilation and air conditioning large system of the station et al.The parameters of the entrance ventilation,the air leakage quantity of platform screen doors?PSDs?,the train departure intervals and the calculating numbers of ventilation and air-conditioning which affect the chang characteristics of the pollutants in the subway station were treated by mathematical methods.Based on the measured impact parameters,the change characteristics of CO₂ in subway station were analyzed with the established equation of variation of pollutant concentration.and analyze the change characteristics of CO₂ in subway station when the parameters were only changed.The results showed that the indoor CO₂ concentration was 0.565% less than 0.1% or 0.15% of the indoor CO₂ concentration limits at 2400 S during the test period;The concentration of CO₂ in the room increases with time,but the rate of growth is decreasing until the CO₂ concentration tends to moderate;Ventilation and airconditioning calculation of the number of 400 per increase,the 2400 S subway station pollutant concentration can increase 0.013%⁰.014%;when the number of ventilation and air-conditioning calculation is 1600,,the CO₂ concentration of the subway station can reach the limit of 0.1% at 2400 S,when the number of ventilation and air-conditioning calculation is 3000,,the CO₂ concentration of the subway station can reach the limit of 0.15% at 2400 S.Finally,a questionnaire survey about indoor air quality was carried out for station staff and passengers,and the HDR value was used to study the dynamic thermal comfort of the passengers.The results showed that the passengers and the station staff are overall satisfied with the air quality in the station,people are generally not satisfied with the body odour and the smell of the bathroom,so there is a big room for improvement;The dynamic thermal comfort of the passengers in the station is more comfortable.