According to NIOSH standards in the United States, masks are divided into three categories:
N: not oil resistant
R: oil resistant
P: long-term oil resistant
Because there will be more oil when cooking, it is recommended to wear R-series or P-series masks. What is the difference between R and P? R-series can prevent oil, but the lifespan is rather short; P-series can prevent oil for a longer period. NIOSH standard suggests that R-series should be used less than 8 hours. If you cook for an hour every day, it is recommended to change the R-series mask once a week, while P-series last longer.