Some laboratories may be equipped with ductless fume hoods to remove chemicals from the air inside the room. These fume hoods often require filters, because they filter the toxic air and redistribute it into the room once it is clean. Carbon filters for fume hood may need to be replaced by the user in order for the model to keep functioning properly. A user can research different testing methods for a fume hood in order to see if the filters are still working efficiently or if they need to be replaced. The workspace in a laboratory where chemicals are used will need an efficient fume hood to keep the air clean and safe for workers to breathe in.