Abstract: An improved apparatus for collecting atmospheric samples, particularly air samples, comprises a sealed collapsible receptacle which includes a hollow body having a base, top and side walls. At least the side walls are constructed of a flexible material. A venting mechanism introduces the atmosphere surrounding the apparatus into the receptacle at a controlled rate. The receptacle includes means for progressively expanding after being compressed. This progressive expansion creates a vacuum within the receptacle, thereby aspirating a measured volume of atmosphere per unit of time through the venting mechanism. Further provided are means for removing a desired quantity or sample of the retained atmosphere from the receptacle, as required.