Abstract: According to an embodiment of the invention, there is provided a method and apparatus for monitoring the air quality, whereby removable filter cartridges or modules containing a monitoring filter can be safely removed and inspected to determine whether or not unsafe pollutants have been introduced to the air within a confined structure such as a building. Another embodiment relates to a valve member for self-actuating when the module is removed to examine the monitoring filter.

Abstract: A pair of variable air volume fans and a set of primary and exhaust air diffusers are in atmospheric communication between a supply of ventilation air that employs the principles of thermal displacement ventilation for purging a designated smoking area of smoke pollutants and the outside atmosphere for receiving the purged polluted air. The volume of ventilation air supplied to the designated area and the volume of air exhausted from the designated area is based upon air quality demand requirements and is determined by a microprocessor coupled to a gas sensor disposed within the designated smoking area.