Inexpensive High Performance Continous Ammonia Monitor

The overall goal of this Project is to develop an innovative inexpensive optical technology and rugged and portable instrumentation for highly sensitive, selective, continuous measurement of atmospheric ammonia for air pollution monitoring. Environmental studies have proven that ammonia presents a significant environmental hazard; therefore, accurate monitoring and control of NH3 concentration is required in order to maintain appropriate air quality levels. Atmospheric ammonia contributes directly and indirectly to acidification, eutrophication, human health and climate change. For air pollution monitoring, the ammonia concentration level of interest is in the parts-per-billion (ppb) range. This application also demands portability, low power draw, and continuous monitoring capability since long term measurements in remote locations are often needed. The Phase I research has demonstrated ammonia measurement precision and detection limit of 1 ppb with signal averaging of 12 s, fast response time (10–30 s) to small step changes in ammonia mole fraction over a wide range of ammonia concentration levels, and high selectivity of ammonia detection. Long-term measurements provide evidence that the method is characterized by high long- term stability (about 1 ppb at low-ppb ammonia levels), which will result in reduced calibration requirements for the Phase II prototype and commercial instrument. Ammonia measurement dynamic range exceeding 5 orders of magnitude has been demonstrated. The Phase II prototype system design is outlined. Incorporation of compact, custom designed analog and digital electronics will make the instrument portable, rugged and easy to operate. The instrument will be capable of remote data logging. Estimated power draw of < 25 W including the long range wireless modem) will allow operating the sensor with a moderately sized solar power supply. The Phase I research has successfully demonstrated the feasibility of the proposed ammonia measurement technology. In Phase II, a compact self-contained prototype instrument will be built, calibrated and extensively field-tested both in-house and at selected facilities. The obtained results provide a solid basis for development, construction, and field testing of the prototype ammonia sensor in Phase II. Successful demonstration of this technology in Phase II will provide the foundation needed to proceed with Phase III commercialization. Potential applications include environmental monitoring, emission control and breath analysis as a medical diagnostic tool.