A filtration system for a fuel cell hybrid propulsion system includes a first stage filter, a second stage filter positioned downstream of the first stage filter, and a third stage filter positioned downstream of the second stage filter and configured to be positioned upstream of a fuel cell system. The first stage filter has first pores with a first mean pore size. The second stage filter has second pores with a second mean pore size. The third stage filter has third pores with a third mean pore size. The second mean pore size is less than the first mean pore size. The third mean pore size is less than or equal to the second mean pore size. The first, second, and third stage filter are structured to filter an airflow prior to being received by the fuel cell system.

A filtration system for a fuel cell hybrid propulsion system includes a first stage filter, a second stage filter positioned downstream of the first stage filter, and a third stage filter positioned downstream of the second stage filter and configured to be positioned upstream of a fuel cell system. The first stage filter has first pores with a first mean pore size. The second stage filter has second pores with a second mean pore size. The third stage filter has third pores with a third mean pore size. The second mean pore size is less than the first mean pore size. The third mean pore size is less than or equal to the second mean pore size. The first, second, and third stage filter are structured to filter an airflow prior to being received by the fuel cell system.

A system includes a non-transitory computer-readable medium having instructions stored thereon. The instructions, when executed by one or more processors, cause the one or more processors to acquire air quality data regarding an air quality of air upcoming, proximate, or entering an air inlet of a filtration assembly, close or restrict the air inlet in response to the air quality data indicating that the air upcoming, proximate, or entering the air inlet is of a quality lower than a quality threshold to substantially prevent dirty ambient air from entering the filtration assembly, and activate air storage to provide an air supply to the filtration assembly when the air inlet is closed or restricted.