摘要目的 评价两类N95型自吸过滤式口罩对六氟化硫(SF6)分解产物的过滤效果.方法 购买市场常用的普通N95型口罩(A)和N95型防酸口罩(B),实验室模拟现场条件测定两类口罩对SF6分解产物——颗粒物、氟化氢和二氧化硫气体的过滤效率,口罩过滤颗粒物效果采用核凝计数器法测定,离子选择电极法和甲醛缓冲液-盐酸副玫瑰苯胺分光光度法分别测定口罩内外空气中氟化氢和二氧化硫浓度.结果 普通N95型口罩和N95型防酸口罩对颗粒物在10～95 L/min的流量下的过滤效果分别为97.50％～100.00％和99.83％～99.99％,均高于95％.0.00～1.99、2.00～3.99、＞4.00 mg/m3氟化物暴露＜1.5 h,N95型防酸口罩氟化氢气体的过滤效率分别为98.83％、99.08％和99.03％,明显高于普通N95型口罩(48.44％、45.71％和47.31％),两种口罩过滤效率的差异有统计学意义(P＜0.05);0.00～2.49、2.50～4.99、5.00～9.99、＞ 10.00 mg/m3二氧化硫暴露＜1.5 h后,N95型防酸口罩的过滤效率分别为95.73％、98.67％、98.14％和97.78％.延长暴露时间(1.5～4 h)后,口罩过滤效率分别下降为91.97％、82.28％、70.12％和58.56％,高浓度组下降更为显著.结论 两类口罩对SF6分解产生颗粒物的过滤效率符合国家要求,N95防酸型口罩对氟化氢和二氧化硫的过滤效果明显高于普通口罩,随使用时间延长,口罩过滤效率下降,应及时更换.

abstractsObjective To assess the filtration efficiency of two N95 filtering-facepiece respirators(FFRs)for the decomposition products of sulfur hexafluoride (SF6).Methods Two types of N95 FFRs (the particulate and the acid-proof respirators) were selected in this study.The decomposition products of SF6,including particles,hydrogen fluoride (HF) and sulfur dioxide (SO2),were measured under experimental condition by using TSI PortaCount Plus,fluorine ion-selective electrodes and spectrophotometer separately.The filtration efficiency was then calculated and compared.Results Both two models of N95 respirators had lowest filtration efficiency larger than 95％ for particles under airflow ranged from 10 to 95 L/min.When exposed to different concentrations of HF (low:0.00～ 1.99 mg/m3,middle:2.00～3.99 mg/m3,high:＞4 mg/m3),the acid-proof N95respirator was more effective than the particulate respirator (P＜0.05) with a filtration efficiency of 98.83％,99.08％,and 99.03％ versus 48.44％,45.71％,and 47.31％.For four SO2 concentration ranges (0.00～2.49 mg/m3,2.50～4.99 mg/m3,5.00-9.99 mg/m3,and ＞10.00 mg/m3),the acid-proof respirator showed a high filtration efficiency within exposure to 1.5 hours:95.73％,98.67％,98.14％,and 97.78％,respectively,when exposure duration extended to 4 hours,the filtration efficiency of the acid-proof respirator decreased to 91.97％,82.28％,70.12％,and 58.56％,respectively.Conclusion Both the particulate and the acid-proof N95 FFRs met national standards on the particulate filtration efficiency.The acid-proof N95 respirator demonstrates to be more effective in filtering HF and SO2 than the particulate respirator.The filtration efficiency could decrease to an unsafe condition under longer exposure duration,timely replacement of respirator is recommended at the workplace.