http://www.3m.co.uk/intl/uk/ohes/segments/healthcare/(9666a)OH_ReusableTechBulletin_lft.pdf
Q – For how long will a set of particulate filters last in use?
A – Filters should be changed when they become clogged with
particulate contaminant. The wearer can determine when this occurs as
it becomes harder to breathe through the filters.
The filters are designed to filter out particles in industrial conditions
and in concentrations much higher than is likely to be encountered in
a pandemic situation.
It is therefore expected that one set of filters will
cover at least one pandemic wave, after which they should be replaced
for infection control reasons.
pandemic wave 點計