COVID-19 Filter Testing
quick lit review
existing standards
mask characterization metrics
- filtration efficiency: percent efficiency of upstream colony-forming units (cfu) to downstream cfu 1
- fit factor: ratio of concentration of microscopic particles outside to particles that leaked in 1
- microbial penetration value: number of microbes passing through the filter per 10 million microbes in the challenge 2
conventional test methods
- Henderson apparatus: generates closed circuit microbial aerosols from a Collison nebulizer at a controlled humidity
- Collison nebulizer - generally a pneumatic atomizer 3
performance difference between pleated hdrophobic filters and electrostatic filters??
Resources
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University of Cambridge DIY mask efficacy testing ↩ ↩2
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AR Wilkes The bacterial and viral filtration performance of breathing system filters ↩