Quote:
Originally Posted by DNSB
Last time I looked at a N-100, it had an exhalation valve which makes it useless for the purpose of preventing you from spraying the neighbourhood with droplets. Given that an N95 mask blocks 95% of 0.3 μm particles and most of the droplets exhaled by humans are in the 5-10 μm and up range, suggesting a N-100 mask with an exhalation valve for less than a 5% increase in inbound filtration is risible.
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I think there are some zones in Spain where they are forbidden because of the valve.