a smoke filter which is useful in containing smoke produced during electrosurgery or laser surgery procedures which has a prefilter layer to contain most of the smoke produced in these surgical procedures and to extend the useful life of the smoke filter , a microporous polymeric membrane layer which acts as a final filtering layer of the smoke filter and disposed between these two layers is a protective foam layer which protects the integrity of the microporous polymeric membrane from damage caused by the prefilter layer .