Recently, waste disposal facilities are constructed as closed systems (CS disposal facilities), because of consideration on the influence to the surrounding environment. In these facilities, gaseous compornents such as methane, carbon dioxide, and hydrogen sulfite, are emitted from the waste. Large ventilation is required to ensure the safety of personnel working in the facilities by keeping the gas concentrations below the admitted level. However, it is difficult to evaluate the total emission rate of these gases, and the actual air exchange rate may be different from the set value because of natural ventilation and channeling of air flow in large space such as CS disposal facilities. The authors have developed a method to evaluate both emission rate and air exchange rate through the measurement of gas concentration change. Furthermore, the effect of natural ventilation caused by outside wind and that caused by temperature difference were compared. Finally, the possibility of environmental improvement by natural ventilation was studied.
