Xa isetyenziswa kwiimeko ze-ozone, umphezulu werabha ukhawulezisa ukuguga, ukuze kubekho isiganeko sokuqandisa esinokubakho sezinto ezingazinzanga kwirabha kuya kukhawulezisa imvula yasimahla (yokufuduka), kukho uvavanyo lwesiganeko sokuqandisa.
