Caadi ahaan loo isticmaalo wax soo saarka ama cilmi baarista sayniska, aqol nadiif ahwaa deegaan la kantaroolo oo leh heer hoose oo wasakhaysan sida boodhka, microbes-ka hawada ka dhasha, walxaha aerosol-ka, iyo uumiga kiimikada. Si sax ah, aqol nadiif ahwaxay leedahay heer wasakhaysan oo la xakameeyey taasoo lagu qeexay tirada qaybaha mitir kuyuubik ee cabbirka walxaha cayiman.