A mail tub in the form of a substantially rigid container and a removable lid which seals the container. The container includes an air inlet port and an air outlet port for sampling air in the mail tub for possible biological contamination, such as anthrax. The container includes structure along the bottom and walls to prevent mail from contacting the walls and bottom. Such structure, in one embodiment, may include raised standoffs along the bottom of the container and channels along the walls to facilitate airflow efficiency through the mail tub when the lid is attached and an air pressure source is applied to the one of the ports. Air samples of the sealed container air are collected for contamination analysis.