Study on calibration of mask protective effect detector based on precise photometer

ABSTRACT

With the outbreak of COVID-19 masks as the most important personal protective equipment, its necessity and importance becomes evident. Particle protective performance, as the key index of masks, the accuracy of its test result is very important. In this study, based on the high-precision photometer, the calibration method of particle protective performance testers for mask is studied. The protective performance is evaluated by the percentage of particle concentration reduction of before and after the mask. Photometric method is a relatively mature technology of particle concentration measurement, with advantages of portability and quick response. In our study, two photometers are used in the calibration. In order to ensure the accuracy, it is necessary to calibrate the two photometers first. Aerosol with concentrations about 1, 10, 20 and 30 mg/m3 is generated in the test chamber, respectively. The filter weight method is used to measure the concentration in the test chamber as the standard values. Within the weighing time, the concentration test results measured by the two photometers are recorded and calibrated with the concentration results measured by the weight method. For the two calibrated photometers, one is used to measure the particle concentration in the test chamber, the other is used to measure the particle concentration in the mask which is attached to the head mold. In this way, the particle protective performance value measured by the instrument can be calibrated. In our experiment, the extended uncertainty of the calibration results are lower than 3%. © 2021 SPIE.