<p>A sampling cartridge (30) for a gas sampling apparatus (10) includes a shell (60) having a cylindrical wall and a sampling window (56) extending through the wall. A pair of spools (78, 80) are coaxially and internally positioned within the shell. The spools are independently rotatable relative to the shell. A first spool (78) may include multiple interval sample collectors (48) while the second spool (80) includes a duration sample collector (50). Each spool also has a window closing surface (58, 58') which is positioned adjacent the window (56) whenever an access door (18) of the gas sampling apparatus is opened. The sampling cartridge may also include a fully encapsulated section (80) of sample collector material as a negative control, and an integral RF tag (90) for storing chain of custody information including personal identification information of a cartridge replenisher.</p>
