Compact, Low-Cost, Long Optical Path, Multiple Gas NDIR Sensor

EPA Contract Number: EPD04016
Title: Compact, Low-Cost, Long Optical Path, Multiple Gas NDIR Sensor
Investigators: McNeal, Mark P.
Small Business: Ion Optics Inc.
EPA Contact: Manager, SBIR Program
Phase: I
Project Period: March 1, 2004 through August 31, 2004
RFA: Small Business Innovation Research (SBIR) - Phase I (2004) RFA Text |  Recipients Lists
Research Category: Air Quality and Air Toxics , SBIR - Air Pollution , Small Business Innovation Research (SBIR)


There is a need for affordable atmospheric and industrial monitoring and controlling systems that can reliably detect and quantify volatile organic compound (VOC) pollution sources within the U.S. Environmental Protection Agency range of regulating standards. These sensors must measure VOC concentration in the range of 1 to 50 ppm to a high degree of accuracy and with a very short response time. Although there are several sensor architectures available that may meet some of these demands, Ion Optics, Inc., submits that only a nondispersive infrared (NDIR) based detection scheme will meet all of them.

The goal of this Phase I research project is to develop an innovative NDIR system based on a highly compact, folded-path optical design. The specially designed optics will enable the use of incoherent broadband sources and sustain high throughput efficiencies over sufficiently long optical path lengths, thus enabling detection limits approaching 1 ppm of hydrocarbon (HC) based VOCs. The proposed system is compact, robust, and readily deployable in the most demanding atmospheric and industrial environments. A prototype system has demonstrated low ppm CO sensitivity in high-pressure, high-humidity, and percent-level background CO2 diesel exhaust streams.

Ion Optics, Inc., proposes further innovative design modifications of the sensor for accurate detection of any VOC as well as determination of the total VOC mass flow. This will be accomplished by strategic selection of band pass filters selected to coincide with the strongest HC absorption peak (common to all VOCs) and one or two satellite peaks unique to the selected constituents. By calibrating the sensor response to known concentrations of high purity gas, the signal processing algorithms then may be adapted for identification and mass analyses of the selected constituents. The estimated cost for this instrument when manufactured in quantity would be less than $100.

Supplemental Keywords:

small business, SBIR, long optical path, nondispersive infrared gas sensor, NDIR, volatile organic compound, VOC, hydrocarbon, HC, sensor architecture, optics, diesel exhaust stream, EPA., RFA, Scientific Discipline, Air, Ecosystem Protection/Environmental Exposure & Risk, Environmental Chemistry, Monitoring/Modeling, Analytical Chemistry, Environmental Monitoring, Atmospheric Sciences, Engineering, Chemistry, & Physics, particle size, monitoring, chemical characteristics, hydrocarbon, aerosol particles, VOCs, gas chromatography, air quality model, diesel exhaust, ambient emissions, chemical detection techniques, emissions, particulate matter mass, particle sampler, nondispersive infrared sensor, VOC emission controls, long optical path, aerosol analyzers, atmospheric chemistry, diesel & gasoline emission sampling

Progress and Final Reports:

  • Final Report