Nitrogen Dioxide and Light-Absorbing Carbon Sensors for Personal Exposure Assessm

描述（由申请人提供）：该项目解决了开发可现场部署的传感器的需求，这些传感器在接触点提供对人体健康有害的空气传播物种的实时定量测量，在这种特殊情况下，是二氧化氮和吸光碳。二氧化氮（NO2）是一种剧毒气体，吸入后会在肺部形成硝酸，并被认为会引发哮喘发作。吸收光的碳（或LAC，分类包括烟灰、黑碳、棕碳、石墨碳等）占可呼吸颗粒的很大一部分。这两个物种都是燃烧系统的副产品，包括机动车辆（尤其是柴油动力）、发电厂、焚化炉和其他固定燃烧器。许多流行病学研究表明，长期接触车辆交通产生的细颗粒和/或气体（如二氧化氮）与各种形式的心肺疾病有关。该计划是Aerodyne研究公司（一家小型企业）和哈佛大学公共卫生学院的合作项目，将涉及便携式传感器的设计、建造、验证和现场测试，该传感器将提供可使用WiFi网络收集的实时数据输出。传感器基于最先进的光学技术，称为腔衰减相移光谱（CAPS），该技术在光学腔中利用非常高的反射率（R>0.9998）反射镜，以提供光学检测这些物种所需的长路径长度（数百米）。这些监测器没有采用测量光强度的比尔定律测量方法，而是测量腔内的平均光子寿命，这个量与吸收物质的浓度直接相关。因此，它们比采用更传统技术的仪器提供更高的灵敏度、稳定性和可靠性。待开发的传感器将提供快速的时间响应（<30秒）和高灵敏度（二氧化氮1 ppbv和LAC 1 5g m-3）；通过Wi-Fi连接到互联网的实时数据流将包含在传感器单元中。这种传感器使用电池可工作8小时或更长时间，其重量与轻型笔记本电脑相当。

DESCRIPTION (provided by applicant): This project addresses the need for the development of field deployable, sensors which provide real- time quantitative measurements at point-of-contact of airborne species that are injurious to human health - in this particular case, nitrogen dioxide and light-absorbing carbon. Nitrogen dioxide (NO2) is a highly toxic gas which when inhaled, causes the formation of nitric acid in the lungs and is thought to trigger asthmatic attacks. Light absorbing carbon (or LAC, a classification which includes soot, black carbon, brown carbon, graphitic carbon, etc.) comprises a significant fraction of respirable particles. Both species are byproducts of combustion systems including motor vehicles (especially diesel-powered), power plants, incinerators and other stationary combustors. Numerous epidemiological studies have shown that long-term exposure to fine particles and/or gases such as nitrogen dioxide produced by vehicular traffic is associated with various forms of heart and lung disease. The proposed program, a collaborative effort between Aerodyne Research, Inc. (a small business) and the Harvard School of Public Health, will involve the design, construction, verification and field testing of portable sensors which will provide real time data output which can be collected using a WiFi network. The sensors are based on a state-of-the-art optical technique, called cavity attenuated phase shift spectroscopy (CAPS), which utilizes very high reflectivity (R>0.9998) mirrors in an optical cavity in order to provide the long path length ((hundreds of meters) required to detect these species optically. Instead of employing a Beer's Law measurement, in which the intensity of light is measured, these monitors measure the average photon lifetime within the cavity, a quantity which is directly related to the concentration of the absorbing species. As such, they provide higher sensitivity, stability and reliability than instruments that employ more conventional techniques. The sensors to be developed will provide fast time response (<30 seconds) and high sensitivity (1 ppbv for nitrogen dioxide and 1 5g m-3 for LAC); real-time data streaming to the internet via a Wi-Fi connection will be included in the sensor unit. The sensors will operate for periods of 8 hours or longer using batteries and will be comparable in weight to a lightweight laptop computer. PUBLIC HEALTH RELEVANCE: These monitors will be used by the air pollution research community to monitor point-of- contact exposure to nitrogen dioxide and light-absorbing carbon. They can also be deployed in factories, power plants, incinerators and other stationary combustor facilities that are subject to occupational health and safety regulations.