Cov iav khoom ntawm cov roj fwj tseem ceeb yog ua-dawb thiab harmless, thiab nws muaj tej yam khoom zoo, Uas yuav tiv thaiv tau ntau yam gases ntawm oxidizing thiab eroding cov khoom nyob rau hauv lub raj mis, Thaum kuj zoo tiv thaiv cov neeg tsis mloog hais components ntawm cov khoom nyob rau hauv lub raj mis los tso rau hauv cov cua. neeg tsis mloog hais
Cov iav siv nyob rau hauv cov roj fwj yog muaj kev ruaj ntseg thiab tu cev, kev tsim txom thiab kev tsim txom, Muaj zoo corrosion kuj thiab acid corrosion kuj, Thiab muaj tshwj xeeb ntim kom zoo dua rau cosmetic ntim, tshwj xeeb tshaj yog rau cov tawv nqaij.