Distributed Optical Fiber Sensor Cable for Air Quality (Air-Sense)

The management of air quality in animal and poultry livestock environments can be challenging, not only due to the required quantitative and qualitative monitoring, but also for determining the air ventilation rates associated with elevated contaminant concentrations at high emission peaks. Ammonia, carbon dioxide, and hydrogen sulfide are generally considered the limiting hazardous gas compounds for animal operations. Elevated levels of air contaminants can cause immediate and long term health effects. Short term effects include eye, nose, or throat irritation, headaches, dizziness, and fatigue. The treatment of short term symptoms can be as simple as isolating the affected person from the contaminated environment. Successive short term exposures, however, can lead to various chronic diseases, including asthma or hypersensitivity pneumonitis. Long term effects, which usually occur from cumulative exposures over a long period of time, can result in respiratory diseases, heart disease, and cancer, and can be severely debilitating or fatal. Current state-of-the-art sensor systems have limited accuracy and high false alarm rates. They are also hampered by high power requirements, making real-time gas sensor analysis impractical. Conventional mass spectrometric and gas chromatography systems, such as the Trace Gas Analyzer and the Volatile Organic Analyzer, are expensive items whose high power requirements and large mass restrict their use in wide air monitoring applications. Relevant studies on air quality measurements, based on gas chromatography with mass spectrometric detection, have been used to detect and identify odor compounds from manure and livestock facilities, but these types of devices are not amenable to multi-contaminant detection, specifically in large area, real-time coverage applications. Thus, there is a pressing need for a unique air sensing and monitoring approach that can quickly and continuously detect and measure concentrations of a variety of gases, at a reasonable cost, and over a wide area. In response, we propose to develop Air-Sense, a high performance, reliable, wide area monitoring system that will be able to conduct simultaneous real-time multi-analyte monitoring with a minimal number of components to meet the air quality guidelines for livestock and animal operations. This will be achieved by developing a distributed optical fiber sensor cable containing multiple sensor fibers for ammonia, hydrogen sulfide, and carbon dioxide in one cable embodiment. Each sensor fiber will consist of a core fiber coated with a colorimetric sensor indicator immobilized in a highly permeable polymer optical cladding. As the sensor fiber is exposed to the target gas, the cladding color will change, and hence affect the light attenuation accordingly. An optical readout module with integrated software and signal processing algorithms will send an alarm when hazardous gas emissions are elevated above 10 percent of Immediately Dangerous to Life or Health (IDLH) levels, and ventilation is required. The sensor cable will allow for multiple sensor detection, thereby adding redundancy to the monitoring process.