Microdischarge-Based Multimetal Emission Monitoring System

EPA Contract Number: EPD04015
Title: Microdischarge-Based Multimetal Emission Monitoring System
Investigators: Herring, Cy
Small Business: Caviton 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: Small Business Innovation Research (SBIR) , Air Quality and Air Toxics , SBIR - Air Pollution


Caviton, Inc., has developed an ideal microsensor for the continuous monitoring of multiple metals. These detection systems rely on microdischarge technology (patent pending), utilizing the power of emission spectroscopy for parts per billion-level sensitivity and laboratory instrument-level selectivity. Microdischarge sensors provide real-time continuous monitoring of metals (and other chemical species) simultaneously using a single detector. The instrument consists of a detector tip, where the discharge is located and sensing takes place; an optical fiber that couples the light from the discharge to a small commercial spectrometer that analyzes the light; and a computer for data processing.

The stable plasma discharge operates in air, and the color of the light from the discharge is altered by any chemicals in the surrounding environment. The spectrometer separates the light into wavelengths, indicating the specific identification of any chemicals present, and is particularly powerful for the detection of metals, including mercury, nickel, lead, cadmium, selenium, and many others. All components of the surrounding environment are broken down by the high-energy discharge to their atomic (and diatomic) constituents, such that metal organics, oxides, and salts are stripped, providing data on the total content of a specific metal. This detection system is compact, rugged, and can be made easy to use, requiring minimal training of technicians and engineers.

Nickel and nickel compounds have been preliminarily characterized in the discharge, as have mercury, silver, copper, aluminum, and chrome, providing estimates of detection limits in the tens of parts per billion. These sensors are capable of operating in harsh environments because of the materials used in construction, and have been operated at more than 1,000°C in previous experiments, with no observable breakdown of detector components. The detector contains no moving parts, adding to the robust nature of these systems.

Supplemental Keywords:

small business, SBIR, microdischarge, multimetal emission monitoring system, emission spectroscopy, sensor, plasma discharge, EPA., RFA, Scientific Discipline, Air, Ecosystem Protection/Environmental Exposure & Risk, RESEARCH, particulate matter, Air Quality, Environmental Chemistry, Monitoring/Modeling, Analytical Chemistry, Monitoring, Environmental Monitoring, Engineering, Chemistry, & Physics, particle size, atmospheric measurements, aerosol mass spectrometer, mercury , Silver, chemical characteristics, human health effects, aerosol particles, air quality models, monitoring stations, emissions measurement, nickel speciation, gas chromatography, air quality model, air sampling, modeling, ambient emissions, aluminum, particulate matter mass, particle sampler, human exposure, multimetal emissions, metal emission monitoring, continuous emissions monitoring, microsensor, microdischarge technology, copper, modeling studies, chrome, aerosol analyzers, atmospheric chemistry, chemical speciation sampling

Progress and Final Reports:

  • Final Report
  • SBIR Phase II:

    Micro-Discharge Based Multi-Metal Emissions Monitoring System  | Final Report