Box Model Approach for Indoor Air Quality (IAQ) Management in a Subway Station Environment

Abstract

Air quality in a subway tunnel has been crucial in most of the subway environments where IAQ could be affected by many factors such as the number of passengers, the amount and types of ventilation, train operation factors and other facilities. A modeling approach has been introduced to manage the general IAQ in a subway station. Field surveys and CO 2 measurements were initially conducted to analyze and understand the relationship between indoor and outdoor air quality while considering internal pollution sources, such as passengers and subway trains, etc. The measurement data were then employed for the model development with other statistical information. For the model development, the algorithm of simple continuity was set up and applied to model the subway IAQ concerned, while considering the major air transport through staircases and tunnels. Monitored CO 2 concentration on the concourse and platform were correlated with modeling results where the correlation values for the concourse and platform were R 2 =0.96 and R 2 =0.75, respectively. It implies that the box modeling approach introduced in this study would be beneficial to predict and control the indoor air quality in subway environments.

Zonal model for predicting contaminant distribution in stratum ventilated rooms

“…The error can be reduced by applying special zoning methods 28,42 . For the special zoning method, the room can be partitioned according to the age of air, 43 thermal plume, 36 boundary wall, 41,44 contaminant source location, 16,33,35,37,38,45 etc. and shows better accuracy than the generalized zoning method.…”

“…Further, the two‐zone and multi‐zone models have been developed to improve the accuracy 32–38 . For the multi‐zone model, the generalized zoning method divides the room into several rectangular parallel‐piped subzones 39–41 .…”

“…Furtaw et al 35 considered the airflow rate between the source‐proximate zone and the remainder of the room as a random value to simulate the disturbance of room air. Song et al 38 built a multizonal model based on the experimentally measured interzonal airflow rate. For sequential box model, 16,45 the backward and forward airflow rate can be derived from the mean air speed, interzonal area, and the airflow balance in every zone.…”

“…35 Further, the two-zone and multi-zone models have been developed to improve the accuracy. [32][33][34][35][36][37][38] For the multi-zone model, the generalized zoning method divides the room into several rectangular parallel-piped subzones. [39][40][41] However, the contradiction between the well-mixed assumption and the realistic non-uniform air distribution results in large errors for the multi-zone model.…”

A novel approach for the modelling of air quality dynamics in underground railway stations

“…Given the previous observations, this study is an attempt at coarse modelling of the PM10 dynamics in underground stations using the approach suggested by Nazaroff [14], based on the well-mixed volume hypothesis, with an adaptation to the subterranean railway context. Recently, Song et al [18] led a similar study aiming at the prediction of CO 2 concentration in the platform and concourse of a station, linking the measurements of CO 2 concentration in the tunnel and an estimation of the train-induced wind after measurements per Kim et al [12].…”