Mask yog ib qho ntawm cov khoom siv tu tawv nqaij hauv lub neej.Cov khoom ntim hauv nws yog nyob rau hauv kev sib cuag nrog daim tawv nqaij, yog li nws yog ib qho tsim nyog los tiv thaiv kev deterioration, tiv thaiv oxidation, thiab ua kom cov khoom tshiab thiab ua tiav kom ntev li ntev tau.Yog li ntawd, cov kev xav tau ntawm cov hnab ntim khoom kuj zoo dua.Peb muaj ntau tshaj 30 xyoo kev ua haujlwm ntawm kev ntim khoom yooj yim.