杀毒面具能保护佩戴者免于吸入空气中的污染物和有毒气体，完全覆盖鼻和口部，也有的也覆盖眼睛或面部其他脆弱的软组织。一些杀毒面具具备呼吸器，常用于军事用途（如战场防护面具）。杀毒面具的滤毒罐在生化环境下，功效持续24小时。

空气中的有毒物质以气态（如第一次世界大战中使用的氯气）或微粒（如许多用生物药剂开发的细菌、病毒及毒素武器）。许多杀毒面具具备两种功用，建筑工程中常用于隔绝焊接产生的烟雾，而在破拆工程中能防止石棉及其他有害微粒，在化工行业中作为预防设备泄漏或清理泄漏物的措施。

防暴警察在骚乱中会用到催泪瓦斯或CS气体清场，杀毒面具因而受到警察和抗争者的青睐。除了功能性用途，杀毒面具还是工业音乐的标志，涂鸦时佩戴面具能隔绝有毒烟雾，城市探险者冒险进入含石棉等有害物质的环境中，也会用到。

The gas mask is a mask used to protect the user from inhaling airborne pollutants and toxic gases. The mask forms a sealed cover over the nose and mouth, but may also cover the eyes and other vulnerable soft tissues of the face. Some gas masks are also respirators, though the word gas mask is often used to refer to military equipment (e.g. Field Protective Mask). The user of the gas mask is not protected from gas that the skin can absorb. Most gas mask filters will last around 24 hours in an NBC (nuclear biological chemical) situation.