PDF(Pubmed)
Abstract：
UNASSIGNED: During hot environment work tasks with whole-body enclosed anti-bioaerosol suit, the combined effect of heavy sweating and exhaled hot humid air may cause the N95 medical respirator to saturate with water/sweat (i.e., water-blocking).
UNASSIGNED: 32 young male subjects with different body mass indexes (BMI) in whole-body protection (N95 medical respirator + one-piece protective suit + head covering + protective face screen + gloves + shoe covers) were asked to simulate waste collecting from each isolated room in a seven-story building at 27-28°C, and the weight, inhalation resistance (Rf), and aerosol penetration of the respirator before worn and after water-blocking were analyzed.
UNASSIGNED: All subjects reported water-blocking asphyxia of the N95 respirators within 36-67 min of the task. When water-blocking occurred, the Rf and 10-200 nm total aerosol penetration (Pt) of the respirators reached up to 1270-1810 Pa and 17.3-23.3%, respectively, which were 10 and 8 times of that before wearing. The most penetration particle size of the respirators increased from 49-65 nm before worn to 115-154 nm under water-blocking condition, and the corresponding maximum size-dependent aerosol penetration increased from 2.5-3.5% to 20-27%. With the increase of BMI, the water-blocking occurrence time firstly increased then reduced, while the Rf, Pt, and absorbed water all increased significantly.
UNASSIGNED: This study reveals respirator water-blocking and its serious negative impacts on respiratory protection. When performing moderate-to-high-load tasks with whole-body protection in a hot environment, it is recommended that respirator be replaced with a new one at least every hour to avoid water-blocking asphyxia.
UNASSIGNED: 32 young male subjects with different body mass indexes (BMI) in whole-body protection (N95 medical respirator + one-piece protective suit + head covering + protective face screen + gloves + shoe covers) were asked to simulate waste collecting from each isolated room in a seven-story building at 27-28°C, and the weight, inhalation resistance (Rf), and aerosol penetration of the respirator before worn and after water-blocking were analyzed.
UNASSIGNED: All subjects reported water-blocking asphyxia of the N95 respirators within 36-67 min of the task. When water-blocking occurred, the Rf and 10-200 nm total aerosol penetration (Pt) of the respirators reached up to 1270-1810 Pa and 17.3-23.3%, respectively, which were 10 and 8 times of that before wearing. The most penetration particle size of the respirators increased from 49-65 nm before worn to 115-154 nm under water-blocking condition, and the corresponding maximum size-dependent aerosol penetration increased from 2.5-3.5% to 20-27%. With the increase of BMI, the water-blocking occurrence time firstly increased then reduced, while the Rf, Pt, and absorbed water all increased significantly.
UNASSIGNED: This study reveals respirator water-blocking and its serious negative impacts on respiratory protection. When performing moderate-to-high-load tasks with whole-body protection in a hot environment, it is recommended that respirator be replaced with a new one at least every hour to avoid water-blocking asphyxia.
摘要：
■在使用全身封闭的抗生物气溶胶服的热环境工作任务中，大量出汗和呼出湿热空气的综合作用可能会导致N95医用呼吸器被水/汗水饱和(即，阻水)。
■32名在全身防护（N95医用呼吸器+一件式防护服+头套+防护面罩+手套+鞋套）中具有不同体重指数（BMI）的年轻男性受试者被要求模拟在27-28°C下从七层建筑中的每个隔离房间收集废物，和重量，吸入阻力（Rf），分析了口罩佩戴前和堵水后的气溶胶渗透情况。
■所有受试者在任务的36-67分钟内报告了N95呼吸器的水阻滞性窒息。当发生堵水时，呼吸器的Rf和10-200nm总气溶胶渗透（Pt）达到1270-1810Pa和17.3-23.3％，分别,是穿前的10倍和8倍。在防水条件下，呼吸器的最大渗透粒径从佩戴前的49-65nm增加到115-154nm，相应的最大尺寸依赖性气溶胶渗透率从2.5-3.5%增加到20-27%。随着BMI的增加,堵水发生时间先增加后减少，而Rf,Pt,和吸收的水都显著增加。
■这项研究揭示了呼吸器堵水及其对呼吸保护的严重负面影响。在炎热的环境中执行具有全身保护的中等到高负载任务时，建议至少每小时更换一个新的呼吸器，以避免水阻塞窒息。
■32名在全身防护（N95医用呼吸器+一件式防护服+头套+防护面罩+手套+鞋套）中具有不同体重指数（BMI）的年轻男性受试者被要求模拟在27-28°C下从七层建筑中的每个隔离房间收集废物，和重量，吸入阻力（Rf），分析了口罩佩戴前和堵水后的气溶胶渗透情况。
■所有受试者在任务的36-67分钟内报告了N95呼吸器的水阻滞性窒息。当发生堵水时，呼吸器的Rf和10-200nm总气溶胶渗透（Pt）达到1270-1810Pa和17.3-23.3％，分别,是穿前的10倍和8倍。在防水条件下，呼吸器的最大渗透粒径从佩戴前的49-65nm增加到115-154nm，相应的最大尺寸依赖性气溶胶渗透率从2.5-3.5%增加到20-27%。随着BMI的增加,堵水发生时间先增加后减少，而Rf,Pt,和吸收的水都显著增加。
■这项研究揭示了呼吸器堵水及其对呼吸保护的严重负面影响。在炎热的环境中执行具有全身保护的中等到高负载任务时，建议至少每小时更换一个新的呼吸器，以避免水阻塞窒息。
