Liquid Crystal-Based End-of-Service-Life-Indicator for Toluene Vapor

描述（由申请人提供）：油漆、汽车、纺织、印刷和制药行业的工人暴露于美国国家职业安全与卫生研究所（NIOSH）认定为致癌物、生殖危害和/或神经毒素的有机溶剂蒸气。这些行业的工人在脸上佩戴配备有呼吸器滤芯的空气净化器呼吸器（APR），以保护自己免受呼吸此类蒸汽的影响。具体来说，每个呼吸器滤筒内填充的活性炭吸附有机蒸汽，以防止它们到达工人的呼吸区。为了最大限度地减少超过碳的吸附能力的风险，这将导致有机蒸汽的穿透和吸入，NIOSH建议在APR中使用寿命终止指示器（ESLI）。虽然ESLI已经被开发用于一些有毒气体（例如，氨），因此没有针对甲苯等有机蒸气的商用ESLI。在没有用于有机蒸汽的ESLI的情况下，NIOSH要求制造商开发（并且用户采用）复杂的药筒更换计划，该计划实施起来很麻烦，容易出错，并且由于诸如温度和湿度的波动、用户的呼吸速率以及蒸汽的浓度等因素而变得复杂。为了解决对可集成到APR中的有机蒸气ESLI的未满足需求，从而满足NIOSH建议并减少与接触有机蒸气相关的健康风险，该提案旨在启动一种全新的基于液晶（LC）的技术的开发，用于报告ESLI中的有机蒸气。开发新技术的动机有两个方面：首先，高成本、对功率的要求和大占地面积不允许基于现有或新兴技术的用于检测挥发性有机化合物（VOC）的传感器被集成为用于呼吸器滤筒的ESLI。其次，与比色读出技术相关的模糊性不符合ESLI应用的NIOSH标准。该提案旨在启动一项技术的开发，该技术有可能产生一种被动和廉价的ESLI，可集成到甲苯呼吸器滤筒中。由于基于LC的技术为气体检测提供了一个无源平台，因此它可以被制造成一种简单的、可嵌入式的格式，这将克服阻止采用现有传感技术作为有机蒸气ESLI的障碍。 公共卫生相关性：多个行业的工人暴露于有机溶剂的蒸气，这些蒸气是健康危害（致癌物，生殖危害和/或神经毒素）。在缺乏适合用作呼吸器滤筒中的有机蒸汽的使用寿命终止指示器（ESLI）的技术的情况下，制造商已经开发出（并且要求工人遵循）复杂的、成本低效率的和模糊的滤筒更换计划，以在呼吸器滤筒不再保护使用者之前更换呼吸器滤筒。该提案旨在启动基于液晶的技术的开发，该技术有可能创造一种 无源和廉价的ESLI传感器，可集成到甲苯呼吸器滤筒中。由于基于LC的技术为气体检测提供了一个无源平台，因此它可以被制造成一种简单的、可嵌入式的格式，这将克服阻止采用现有传感技术作为有机蒸气ESLI的障碍。

DESCRIPTION (provided by applicant): Workers in painting, automobile, textile, printing, and pharmaceutical industries are exposed to vapors from organic solvents that are recognized by National Institute of Occupational Safety and Hygiene (NIOSH) as carcinogens, reproductive hazards, and/or neurotoxins. Workers in these industries wear Air Purifier Respirators (APRs) equipped with respirator cartridges on their faces to protect themselves from breathing such vapors. Specifically, activated carbon that is packed within each respirator cartridge adsorbs organic vapors to prevent them from reaching the workers' breathing zone. To minimize the risk of exceeding the adsorption capacity of the carbon, which would result in breakthrough and inhalation of organic vapors, NIOSH has recommended the use of end-of-service life indicators (ESLI) in APRs. Although ESLIs have been developed for some toxic gases (e.g., ammonia), there are no commercial ESLIs available for organic vapors such as toluene. In the absence of ESLIs for organic vapors, NIOSH requires manufacturers to develop (and users to adopt) complex cartridge- changing schedules that are cumbersome to implement, prone to error, and complicated by factors such as fluctuations in temperature and humidity, breathing rate of the user, and the concentration of the vapors. To address the unmet need for an ESLI for organic vapors that can be integrated into APRs and thereby meet the NIOSH recommendations and reduce the health risks associated with exposure to organic vapors, this proposal seeks to initiate the development of a fundamentally new liquid crystal (LC)-based technology for reporting organic vapors in ESLIs. The motivation for the development of the new technology is two-fold: First, the high cost, requirement for power, and large foot print does not allow the sensors based on existing or emerging technologies for detection of volatile organic compounds (VOC) to be integrated as ESLIs for respirator cartridges. Second, the ambiguities associated with colorimetric readout technologies do not meet NIOSH standards for ESLI applications. This proposal seeks to initiate the development of a technology that has the potential to create a passive and inexpensive ESLI that can be integrated into respirator cartridges for toluene. Because the LC-based technology offers a passive platform for gas detection, it can be fabricated as a simple, cartridge-mountable format that will overcome the barriers that have prevented adoption of existing sensing technologies as ESLIs for organic vapors. PUBLIC HEALTH RELEVANCE: Workers in multiple industries are exposed to vapors from organic solvents that are health hazards (carcinogens, reproductive hazards, and/or neurotoxins). In the absence of technologies suitable for use as end-of-service-life-indicators (ESLI) for organic vapors in respirators cartridges, manufacturers have developed (and workers are required to follow) complex, cost ineffective, and ambiguous cartridge- changing schedules to replace the respirator cartridges before they no longer protect the users. This proposal seeks to initiate the development of a liquid crystal-based technology that has the potential to create a passive and inexpensive ESLI sensor that can be integrated into respirator cartridges for toluene. Because the LC-based technology offers a passive platform for gas detection, it can be fabricated as a simple, cartridge-mountable format that will overcome the barriers that have prevented adoption of existing sensing technologies as ESLIs for organic vapors.