32 plays a significant role in activation of the gas treatment unit 14 as will become apparent hereinafter 0041 fig4 a and 4b illustrate how the lightweight and compact respirator hood assembly 11 is easily carried by the user 18 as a carry along fig4 a or may fit within a briefcase 44 fig4 b if carried as a carry along as shown in fig4 a the assembly 11 can include rings not shown or the like for attaching an auxiliary carrying strap 42 desirably the respirator hood assembly 11 fits into a portion of a typical small briefcase 44 analogously the respirator hood assembly 11 can be carried in a purse or backpack not shown the convenient carrying and compact storage features of the respirator hood assembly 11 are important in that they provide immediate availability of the respirator hood 10 to the user 18 these features along with the automatic activation of the gas treatment unit 14 discussed below and simple donning allow he respirator hood 10 to be in fill use within seconds rapid deployment can be critical to the health or even survival of the user 18 in fig5 an arrow 46 indicates the gas flow path gases enter the gas treatment unit 14 firstly through an opening 48 in a housing 50 that accommodates the gas treatment unit 14 the.