smoke evacuation apparatus designed to provide safe and efficient filtration and evacuation of smoke plume generated by laser - surgical , electrosurgical , radiosurgical , and electrocautery devices . to ensure capture and removal of the smoke plume , several stages of filtration processes , including a first micro - pre - filter to filter out the most particles and harmful elements at this stage followed by passage of the smoke plume through a main vacuum suction unit and filter to filter out the remaining particles and any odors , are employed . preferably , the main filter comprises fine charcoal through which the air flows radially which helps remove the odors . in a preferred embodiment , means are provided to monitor the degree of pollution of the main filter to warn users when it is desirable or necessary to replace the main filter . in addition , means are provided to ensure reasonably constant air mass flow to protect against significant clogging of the system which could result in undesirable passage of harmful particles into the environment .