Protect Filter Why

Protect Filter Why
Why don’t air filters completely protect against second hand smoke?

My boyfriend says that, because air filters protect against things that are 0.5 microns and smaller, they should completely protect against all the harmful components in second hand smoke, but I can’t find any Web sites that agree with him. Soooo why is it that air filters don’t completely filter out harmful components of secondhand smoke? Are the components smaller than 0.5 microns?

That is 0.5 microns or larger, not smaller.

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