Once the sampler is loaded and placed in its airtight vial, it should be kept at standard room temperature, as long as it is to be taken on site within several days.
If the loaded sampler is not going to be used for several days, it is best to place it in a refrigerator (not a freezer). It should be removed from the refrigerator about 12 hours before exposure for the purpose of equilibrating to the room temperature. This is done to prevent condensation from forming on the pad. Moisture is the enemy of the coated pad, as it can remove some of the collecting material.