A Compact, Low-Cost, Near-UV Sensor for Chlorine Dioxide

Southwest Sciences proposes the development of an optical, near-ultraviolet chlorine dioxide sensor having a measurement range for about 0.01 to 2000 ppm with a response time of less than 10 seconds. The sensors will be compact - about the size of a 1quart milk carton including electronic and optics - operate a low power, and be outfitted with wireless communications interface to permit remote, unattended operation. Intrinsically safe design is possible. The proposed measurement method is linear, free of hysteresis and free of interference from common atmospheric gasses as well as urban and industrial pollutants. The sensors will operate well as high humidity and will be able to tolerate moisture condensation. Analyzers will retain calibration for extended periods (many months). Commercial applications include real-time sensors for monitoring and controlling ClO2 decontamination of building and other enclosed spaces, and for monitoring chloride dioxide water purification processes and facilities. In Phase II, we will try to extend the diode-laser method to chlorine detection; that will provide extra utility for characterization and for monitoring combined ClO2/Cl2 decontamination and purifications processes. We also plan to participate in EPA¿s Environmental Technology Verifications (ETV) program in order to establish performance specifications for the prototype analyzer.