Gas Filters are gas matching functions that will either accept or reject gas, depending on the type of the gas. Gas Pumps and Gas Collectors use Gas Filters to distinguish between gas types to determine which gas types they operate with.

A key feature of all Gas Filters is that air, also considered a gas type, is always accepted.

There are two types of Gas Filters:

• Including type: Only accepts gas that matches a specific gas type, or matches air. This type of filtering is applied with Including Gas Samplers.
• Excluding type: Only accepts gas that does not match a specific gas type, or matches air. This type of filtering is applied with Excluding Gas Samplers.