The Theory Research For Single Surface Volatile Organic Compounds Emission Characteristics From Dry Building Materials And Its Application

The real health effects of air pollution depend on the concentrations experienced by people rather than those recorded by stationary air quality monitors located outdoors for people spend 70%~90% of their time indoors. But indoor air quality in one room depend on outdoor air quality and indoor pollutant sources. Recently, some of the research results show that the indoor air pollution caused by modern building decoration materials in release volatile organic compounds (VOCs) is one of the main factors. As we all know, natural ventilation is a kind of energy-saving and environment-protecting ventilation mode and it can provide better indoor air quality, so it is a very good ventilation mode.Firstly,from pollutant source point, this paper develops and describes a new model for single surface volatile organic compounds(VOCs) emission characteristics from dry building materials. Compared to other models,it takes into account the situation that when the initial concentration of VOC in the room and the inlet concentration are not zero. Moreover, the form of the solution is fully analytical, so it can be calculated without iteration. Therefore, this model could be used more universally. The model is proved effective and correctness by using the known experiment results and the discrete solution of equations for its verification. This model can be used in three ways: First, we can calculate the concentration of VOC in a room; second is to calculate the amount of VOC emitted from building materials; Third, we also can calculate the ventilation time or ventilation rate with given building materials and the concentration of VOC in a room, so to provide the basis for the design of air-conditioning system. Due to single surface VOC emission process from dry building materials is under the influence of various factors, basis on this new model, we also discuss the influences under the factors of flow speed, temperature, inlet concentration and initial pollutant concentration in a room.Secondly, we obtain the criterion equation between VOC emission rate from building materials and the dimensionless parameter in this model. It is fits well with the analytical solution formula. With this relationship equation, we give two methods for scaled the results for a given building material in a test chamber to those under real conditions, if the dimensionless parameters are within the appropriate region for the correlations. The relationship also explicitly explains the impacts of gas-phase mass transfer coefficient, load ratio, and air exchange rate on the VOC emission rate, which determines the feasibility of assuming that the VOC emission rate in real conditions is the same as that in the test chambers.Again, depending on the new model, we consider the interactions of natural ventilation and this model, and take it as a theoretical guidance, we also design a simple software for assessing the indoor air quality.Finally, the relationship of temperature, ventilation and the new model is plainly researched when considered heat source effect. Then a dynamic model is developed to predict short-term indoor air pollutant concentration and indoor temperature. The model can accurately simulate indoor air quality and indoor temperature changes.