Case Study On Characteritics Of Gas Pollutants In Residential Underground Garage Under The Condition Of Natural Ventilation

With the rapid growth of private car ownership and the increasing number of highrise residential constructions, the underground garage is becoming more important for rencent years. As a result, the air quality has caused widely concern. This paper selects a natural ventilation underground garage in Harbin as a typical garage for field test to study the characteristics of CO, TVOC, HCHO and NH3.Firstly, ventilation, temperature and humidity and the traffic flows are analysed. The center point is selected as the regular test point for CO, TVOC, HCHO and NH3. Five points are selected to do the horizontal distribution test and the points of 0.3m, 1.5m and 2.5m in hight in the center for the vertical distribution.Secondly, the spatial and temporal distribution of the pollutant concentrations is given in this paper. The horizontal and vertical distribution is discussed, and it shows that the conceration of pollutants is higher in the out-cars centralizend and air-exhaust side while even in the vertical direction. It further discussed the daily and periodically variation features. It shows that the characters of the working and rest days remain similar in different cycles. The conceration of CO and TVOC exceeds the limits in winter. The changes of correlation coefficient shows that the correlation between different pollutants changes in different cycles, and CO, TVOC and HCHO are highly liner related in winter. When CO gets 25 ppm, TVOC has already been over 1.0ppm. The influence analysis is finished by the partial correlation coefficient and the gray correlation degree methods and it shows that the out flow of cars is the main factors of CO, TVOC and HCHO concentration changes.At last, the model of pollutant concentration changes is established based on the ventilation dilution equation, the application conditions and the physical meaning of the fitting parameters are given. The definition of the ventilation frequency demand is given which shows the condition for the using of natural ventilation for underground garage. The ventilation control strategies are given for the selected garage.