Crouch K G, McGlothlin J D, Johnston O E
U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Cincinnati, Ohio 45226, USA.
AIHAJ. 2000 Sep-Oct;61(5):753-6. doi: 10.1080/15298660008984587.
A review is given of National Institute for Occupational Safety and Health (NIOSH) efforts to control N2O at a pediatric dental operatory from 1978 to the present. Measurements of N2O concentrations were made on four occasions before and after installation of different controls, using an infrared analyzer. Air velocity and volumetric flow measurements also were taken, Video imaging was done in some cases simultaneously with real-time N2O measurements to correlate work practices with exposure data. An infrared imaging system was used to identify sources of N2O. Critical components of resulting recommendations for control include monitoring of N2O concentrations; use of engineering controls, such as a scavenging mask, an effective dilution ventilation system, and auxiliary exhaust; good work practices; maintenance of the equipment; and worker education. Data presented strongly supports the hypothesis that better implementation of controls leads to reduction of N2O exposures. N2O concentrations were reduced by a factor of 61 from their initial levels. The current NIOSH recommended exposure limit of 25 ppm TWA during the time of N2O administration appears to be achievable.
本文回顾了美国国家职业安全与健康研究所（NIOSH）自1978年至今在儿科牙科诊疗室控制一氧化二氮（N2O）的工作。在安装不同控制措施前后，使用红外分析仪对N2O浓度进行了四次测量。还进行了风速和体积流量测量，在某些情况下，视频成像与实时N2O测量同时进行，以将工作实践与暴露数据相关联。使用红外成像系统识别N2O的来源。控制建议的关键组成部分包括监测N2O浓度；使用工程控制措施，如清除面罩、有效的稀释通风系统和辅助排气；良好的工作实践；设备维护；以及工人教育。所呈现的数据有力地支持了以下假设：更好地实施控制措施可降低N2O暴露。N2O浓度从初始水平降低了61倍。目前NIOSH建议的在施用N2O期间8小时时间加权平均容许浓度为25 ppm似乎是可以实现的。
