a similar gas mixture from a small unit to fill 1 ml of air with 1 percent of ch4 100 ppm co and 40 ppm h 2 s one may need a volume of 10 ul of ch 4 an approach of the present system may include the following items first one may make long band of bubble foil with bubbles of about 20 ul out of aluminized polymer like mylar and fill them with a gas mixture without overpressure second one may roll the band of bubbles onto a cylinder and pull off one bubble at a time third for each bump test one may puncture one bubble with a u201c hammer u201d like a cap gun does when it generates a shooting sound from a roll with chemicals fourth one may let the gas mix with 2 ml of air in an enclosed volume and pump air through the volume fifth one may pump the gas mixture over the sensors a roll for 800 2 ml pulses could have a width of about one inch and a diameter of about two inches which does not seem prohibitively large for fixed sensors bubble foil appears to be the easiest approach for fixed sensors this approach may be used for testing portable sensors such as those implemented in personal badges an alternative to gas generation may include some of the following items fig1 shows a blister pack or bubble foil 10 the bubble foil 10 may have bubbles 13 made out of aluminum foil 11 for a base and have aluminum or an aluminized polymer e g mylar 12 for the bubble side the aluminum foil 11 and the aluminum or aluminized polymer 12 may be joined and sealed by heat or ultrasound.