In a fuel cell, an air filter is crucial for ensuring the efficient and reliable operation of the system. The purpose of an air filter is primarily the removal of contaminants, particularly particulates (it removes dust pollen, and other particulate matter that could damage or clog the fuel cell) and chemical contaminants (removing chemical pollutants like sulfur compounds, hydrocarbons, and nitrogen oxides, which can poison the catalysts in the fuel cell and reduce its efficiency).