Landon Paul, Breysse Patrick, Chen Yuju
Department of Environmental Health, Division of Environmental Health Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205-2179, USA.
Am J Ind Med. 2005 Apr;47(4):364-9. doi: 10.1002/ajim.20152.
Both continuous and impact noise exposures of rail yards and railways have been historically understudied. We summarize noise exposures to rail workers at a large chemical facility in North America.
Rail workers were surveyed over the course of three 12-hr shifts. Personal noise dosimeters were used to derive a 12-hr time-weighted average (L(AVG)), an 8-hr time-weighted average (L(TWA)), and a percent dose. Peak and maximum sound levels were also recorded during each sampling period. Six workers were sampled on three separate days for a total of 18 full-shift noise samples.
Full-shift noise exposures were all below the Occupational Safety and Health Administration's (OSHA) permissible exposure limit (PEL) and action level for a 12-hr workday. Peak impact sound levels exceeded 140 dB in 17 of 18 samples (94%) with a mean peak sound level of 143.9 dB. Maximum continuous sound levels were greater than 115 dBA in 4 of 18 samples (22%) with a mean maximum sound level of 113.1 dBA. The source of peak impact sound levels was a daily exposure to a concussion caused by a sudden break in a freight airline.
Rail workers at this facility are at risk of noise induced hearing loss from high impact noise exposures. Peak impact and maximum continuous sound levels can be attenuated through the use of hearing protection or by increasing distances from railroad noise sources.
历史上对铁路货场和铁路的连续噪声暴露及冲击噪声暴露的研究都不足。我们总结了北美一家大型化学工厂铁路工人的噪声暴露情况。
在三个12小时轮班期间对铁路工人进行了调查。使用个人噪声剂量计得出12小时时间加权平均声级(L(AVG))、8小时时间加权平均声级(L(TWA))和剂量百分比。在每个采样期间还记录了峰值和最大声级。在三个不同的日子对六名工人进行了采样,共获得18个完整轮班的噪声样本。
整个轮班的噪声暴露均低于职业安全与健康管理局(OSHA)规定的12小时工作日的允许暴露限值(PEL)和行动水平。18个样本中有17个(94%)的峰值冲击声级超过140分贝,平均峰值声级为143.9分贝。18个样本中有4个(22%)的最大连续声级大于115 dBA,平均最大声级为113.1 dBA。峰值冲击声级的来源是每天受到货运飞机突然断裂产生的冲击。
该工厂的铁路工人面临因高冲击噪声暴露而导致噪声性听力损失的风险。通过使用听力保护装置或增加与铁路噪声源的距离,可以降低峰值冲击声级和最大连续声级。