Through experimental testing of 8 commonly used types of anti haze kouzhao, the regression curve analysis method was used to obtain the functional form of the respiratory resistance of anti haze kouzhao over time. At the same time, the recommended usage time for various types of kouzhao was also given through experimental data statistics. It is suggested that N90 and N95 non-woven anti haze kouzhao should not exceed 11-12 hours under mild air pollution and 8-10 hours under moderate air pollution; while N95 kouzhao made of cotton fabric should not exceed 7 hours under mild air pollution and 6 hours under moderate air pollution.