Indoor Air Biocontaminant Control by Means of Combined Electrically Enhanced Filtration and OAUGDP Plasma Sterilization

EPA Contract Number: 68D99025
Title: Indoor Air Biocontaminant Control by Means of Combined Electrically Enhanced Filtration and OAUGDP Plasma Sterilization
Investigators: Helfritch, Dennis J.
Current Investigators: Kelly-Wintenberg, Kimberly
Small Business: Environmental Elements Corporation
Current Small Business: Atmospheric Glow Technologies
EPA Contact: Richards, April
Phase: II
Project Period: September 1, 1999 through September 1, 2001
Project Amount: $224,715
RFA: Small Business Innovation Research (SBIR) - Phase II (1999) Recipients Lists
Research Category: Air Quality and Air Toxics , SBIR - Air Pollution , Small Business Innovation Research (SBIR)


The filtration of pathogens from indoor air is hindered by two characteristics of the organisms: extremely small size and the ability to propagate. It is well known that the effective filtration of particles less than one micrometer is difficult. It also is known that the organisms captured by the filter can flourish on the filter surface and migrate through the filter, only to be reintroduced into the airstream.

The use of electric fields and electric discharges can address these challenges. Enhancement of filter capture efficiency through the application of electrostatic fields is well established. Polarization effects brought about by a direct current (DC) electric field produce an attractive force between particles and filter fibers resulting in significantly enhanced filter efficiency, especially for small particles. The sterilization of surfaces through exposure to the University of Tennessee's One Atmosphere Uniform Glow Discharge Plasma (OAUGDP) has been demonstrated to be very effective. Microbe destruction occurs through attack by atomic oxygen and oxygen radicals created by the plasma.

Thin electrodes, attached to both sides of a filter, yield enhanced capture efficiency when a DC voltage is applied across these electrodes. Furthermore, periodic radio frequency alternating current energization of the electrodes generates a plasma on the filter surface that kills captured organisms. This project demonstrates these effects by constructing and operating such a filter.

Infectious disease takes a tremendous toll on people and on the U.S. economy. The causes of many of these diseases are airborne pathogens. For example, in 1994 there were more than 90 million cases of influenza nationwide resulting in 170 million bed days. This led to more than 69 million work-loss days and $13.2 billion of lost earnings.

A Phase I program has shown that the field-enhanced plasma-sterilized filter will effectively capture and kill airborne microorganisms at reasonable energy use. It is anticipated that the filter will represent a solution for the problem of indoor air pathogens for both public and private buildings.

Supplemental Keywords:

small business, SBIR, indoor air, engineering, chemistry, EPA., RFA, Scientific Discipline, Air, particulate matter, Chemical Engineering, air toxics, Environmental Chemistry, Chemistry, Biochemistry, indoor air, tropospheric ozone, Engineering, Chemistry, & Physics, Environmental Engineering, ambient air quality, electrostatic removal, biofilter , electrically enhanced filtration, particulates, biocontaminant control, air pollutants, stratospheric ozone, aerosol particles, ambient air, biofilter, filtration, bacteria filtration, filtration technology, indoor air chemistry, air pollution, plasma sterilization, plasma filter, particulate exposure, biocontaminants, OAUGDP, aerosol, indoor air quality, biofiltration systems, ambient pollution control, ambient submicron particles, air quality

Progress and Final Reports:

  • Final Report

  • SBIR Phase I:

    Indoor Air Biocontaminant Control by Means of Combined Electrically Enhanced Filtration and OAUGDP Plasma Sterilization  | 1999 Progress Report  | Final Report