Improved Respirator Carbons for Ammonia Hazards

改进呼吸器碳以应对氨危害

• 批准号: 9139745
• 负责人: GIRISH SRINIVAS
• 金额: $ 15万
• 依托单位: TDA RESEARCH, INC.
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-15 至 2017-09-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9139745
• 关键词: Improved; Respirator; Carbons; Ammonia; Hazards

 DESCRIPTION (provided by applicant): TDA Research, Inc. (TDA), proposes to develop new types of activated carbons to protect the more than 700,000 agricultural workers, who according to the CDC are at risk from exposure to toxic levels of ammonia. In addition to agricultural workers, fire fighters, first responders and chemical industry personal are also at risk. OSHA rates 300 ppmv NH3 in air as Immediately Dangerous to Life and Health (IDLH). Levels of 150 ppmv have led to permanent scarring of lung tissue causing chronic respiratory illness. Ammonia readily dissolves in water and damages moist tissues of the body, and especially the eyes. Initial eye-tissue damage and necrosis caused by ammonia is often followed by conjunctivitis and secondary eye infection. Chronic exposure to even 6 ppmv has caused eye damage and temporary blindness, and high levels have caused permanent blindness. In poorly-ventilated buildings of the over 257,000 Animal Feeding Operations (AFO) and the over 15,500 Concentrated Animal Feeding Operations (CAFO), for example, NH3 levels routinely exceed 50 ppmv, and with low winter-ventilation rates, agricultural workers are often exposed to 100-200 ppmv. Advocates of public health are recommending that children down-wind of ammonia-releasing operations should not be exposed to more than 300 ppbv NH3 in air. Hitherto, workers have relied on respirators incorporating activated carbons produced from pyrolysis of coconut shell-a technology developed for World War I gas masks. However, the best of these has recently been discontinued, leaving manufacturers of ammonia respirators scrambling and with a critical need for new supplies of activated carbons that are specific for use in ammonia respirators. Most off-the-shelf activated carbons, designed for other purposes, are ineffective for NH3 uptake. Staff at TDA has over 20 years of experience in the design of specialty sorbents, supplying over 100 metric tons per year to customers, worldwide. In preliminary studies, TDA has demonstrated that a treated activated carbon performs significantly better for NH3 uptake compared to activated carbons now currently available. In Phase I, the carbons will be optimized for NH3 uptake. In Phase II, carbons will be scaled up for commercialization.