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

描述(申请人提供)：油漆、汽车、纺织、印刷和制药行业的工人暴露在有机溶剂中的蒸气中，这些有机溶剂被美国国家职业安全与卫生研究所(NIOSH)认定为致癌物质、生殖危害和/或神经毒素。这些行业的工人在脸上佩戴装有呼吸器墨盒的空气净化器呼吸器(APR)，以保护自己免受此类蒸气的影响。具体地说，每个呼吸器内填充的活性碳会吸附有机蒸汽，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，从而导致有机蒸气的突破和吸入，NIOSH建议在APR中使用服务终止寿命指标(ESLI)。尽管已经为一些有毒气体(例如氨)开发了ESLI，但还没有可用于甲苯等有机蒸气的商业ESLI。在没有有机蒸气的ESLI的情况下，NIOSH要求制造商制定(和用户采用)复杂的换筒时间表，这些时间表执行起来很麻烦，容易出错，而且受到温度和湿度、用户呼吸频率和蒸汽浓度波动等因素的复杂影响。为了满足对可纳入原料药的有机蒸气的ESLI未得到满足的需求，从而满足NIOSH的建议，并减少与接触有机蒸气相关的健康风险，该提案寻求启动一种基于液晶(LC)的全新技术的开发，用于报告ESLI中的有机蒸气。开发这项新技术的动机有两个：首先，高昂的成本、对功率的要求以及巨大的占地面积使基于现有或新兴技术的挥发性有机化合物(VOC)检测传感器无法集成为呼吸器药筒的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。这项提议旨在启动一项技术的开发，该技术有可能创造一种无源和廉价的ESLI，可以集成到甲苯的呼吸器药筒中。由于基于LC的技术为气体检测提供了无源平台，因此可以将其制造为一种简单的、可安装在墨盒上的格式，从而克服阻碍采用现有传感技术作为有机蒸气ESLI的障碍。 与公共健康相关：多个行业的工人暴露在危害健康的有机溶剂蒸气中(致癌物质、生殖危害和/或神经毒素)。由于没有适合用作呼吸器药筒中有机蒸气的寿命终止指示器(ESLI)的技术，制造商制定了复杂、成本效益低且含糊不清的更换药筒的时间表，以便在呼吸器药筒不再保护用户之前更换它们。该提案寻求启动基于液晶的技术的开发，该技术有可能创造出 无源和廉价的ESLi传感器，可集成到甲苯呼吸药筒中。由于基于LC的技术为气体检测提供了无源平台，因此可以将其制造为一种简单的、可安装在墨盒上的格式，从而克服阻碍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.