Provision of Consultancy Services for estimation of particle filtration efficiency of face masks in community setting

  • Ching Lam (Lead consultant)

Activity: Consultancy


Methods This project will employ an exploratory and descriptive design. Settings The estimation will be performed in Squina International Centre for Infection Control, where has equipped with particle filtration efficiency (PFE) system. Sample and sample size A total of 500 materials, including but not limited to face masks, filter materials, paper, towel, and cloths, which should be available to well fit to the system, will be received from the service recipients. Measurement Filtration efficiency: The self-developed particle filtration efficiency (PFE) system has been established to estimate the filtration ability of the sampled mask on selected aerosols size based on the ASTM F2299-03 [7]. The test procedure will be performed to evaluate the PFE of given face mask by comparing the artificial generated aerosols in upstream (i.e., outside mask) of the test article to that in downstream (inside mask). The aerosols were generated by Sodium Chloride and kept in the buffer chamber until an optimum test environment, including aerosol concentration between 107 and 108 particles/m3, humidity of 30-50% (+ 5%), and temperature of 21°C (+ 3°C). Two sets of Optical Particle Counter (Grimm Aerosol Spectrometer, Model 1.109) [8] were used to capture and count the aerosols with the size of 0.3 µm and 1 µm at upstream and downstream. Five to ten pairs of consistent data (<3% variation of particle count) will be used to estimate the filtration efficiency. This system was validated with Automated Filter Tester (TSI Model 8130A as gold standard for 0.3 μm PFE) [9] by comparing the known 0.3 μm PFE materials from 40.33% to 99.99% (Figure 1). Results indicated that the PFE difference ranged from -6.81% to 3.85% (mean = -1.65, SD 3.47). Concurrent validity that correlated the two set of PFE scores was also satisfactory (r = 0.99, p < 0.001). The above result has been published in the renowned journal [6]. We can perform filter inspection by the use of optical microscope to examine the consistency and thickness of the fibre upon request or indication (determined by the consultant).
Period11 Jun 202011 Jun 2021
Work forFugro Technical Services Ltd., Hong Kong
Degree of RecognitionLocal