Auxiliary ventilation for the control of nitrous oxide in a dental clinic.
Mickelsen RL; Jacobs DE; Jensen PA; Middendorf PJ; O'Brien DM; Fischbach TJ; Beasley AA
Appl Occup Environ Hyg 1993 Jun; 8(6):564-570
The use of local exhaust ventilation to reduce the concentration of nitrous-oxide (10024972) in a dental clinic was investigated. Area samples were collected 15 inches from the patient, and personal samples were collected on the dental hygienist and dental assistant. All procedures were performed in a dental clinic serving handicapped persons. A scavenging system was used alone or with one of three local exhaust ventilation systems. The three local exhaust ventilation systems had a hood opening located near each patient's mouth, a conveying duct, and a 10 inch centrifugal fan with a 1 horse power motor located outside the building. All the nitrous- oxide delivery systems used within the clinic had leaks but these were judged to be nonsignificant. The nose cup scavenging system was not effective in lowering the nitrous-oxide levels below the suggested limits. One system which consisted of a scavenging system and a 3 inch diameter flexible duct connected to a fan was able to control exposures of the dental hygienist to below 60 parts per million (ppm). Another system which consisted of a scavenging system and a 6 inch diameter flexible duct connected to a fan kept the exposure to the dental hygienist below 135ppm. The authors conclude that even though the exhaust systems tested were not able to completely control nitrous-oxide exposures in the clinic, the use of auxiliary ventilation is a promising technique that should be studied further.
NIOSH-Author; Air-quality-control; Occupational-exposure; Control-technology; Dentistry; Ventilation-systems; Anesthetics; Toxic-gases
Applied Occupational and Environmental Hygiene