It is believed that the area under the curve could represent the ethanol concentration in the feed more accurately than by using the peak current value [38]. In this study, the sensitivity, peak current and charge densities follow the same trend, which shows the highest sensitivity, current and charge densities for 40% Pt/C and the lowest ones for 10% Pt/C loading. The regression least square coefficient (R2) shown in Fig. 5(c) and (d) revealed that all of the sensors with different Pt loadings had acceptable linear response toward changing ethanol concentration from BAC 0.005 to 0.2%. The sensor with 20% Pt/C and 0.2 mg/cm2 loading only showed poor linearity at BACs between 0.005 to 0.1% and could not perform as good as other sensors across the full range of BACs. The bestlinearity was obtained from the sensor with 30% Pt/C and 0.25 mg/cm2 loading, revealing more than 99% linearity. Since obtaining the peak current density is faster than the charge density, employing the peak current density method for these sensors to measure the ethanol concentration is preferred. Thus,the sensor can be recovered for the next use faster. It was discovered that the measurement accuracy would not be changed if the peak current method is used instead of charge density to measure the ethanol gas concentration for a fresh sensor operating at room temperature.