A filtration device including a fluid-impermeable housing having a gas inlet and outlet, and containing within the housing first filter media particles of an extended surface area substrate and containing at least one metal impregnant, and second filter media particles of an extended surface area zirconium hydroxide substrate and containing zinc (hydr)oxide. The first or second filter media particles also contain an amine-functional material. The device may be used in atmospheres containing various harmful gases, and may provide particularly useful improvements in breakthrough times for nitrogen dioxide, hydrogen sulfide, ammonia and formaldehyde compared to a device containing only the first filter media particles or only the second filter media particles.