TRJ Environmental

Ted Johnson


  • M.S., Environmental Science and Engineering, University of North Carolina, Chapel Hill, North Carolina, 1976.
  • B.S., Electrical Engineering (Honors), North Carolina State University, Raleigh, North Carolina, 1971.

Employment History

1995 - Present
TRJ Environmental, Inc., Chapel Hill, NC: Research Director responsible for exposure assessment and air quality analysis. Company founder.
1977 - 1995
IT Corporation, Durham, NC: Manager of Durham branch office (1993 - 1995). Manager of the Air Quality Analysis and Assessment Group (1977 - 1995). Responsible for development of population exposure models, statistical analysis of air quality data, and assessment of proposed ambient air quality standards.
1973 - 1975
Exide, Inc., Raleigh, NC: Design Engineer responsible for development of static inverters for uninterruptible power supply (UPS) systems. Project Engineer responsible for coordinating design, testing, and installation work on step-wave UPS systems.
1972 - 1973
Catalytic, Inc., Philadelphia, PA: Electrical Engineer on the Olin Chemical project involving various phases of power distribution and control. Student and later instructor of the Catalytic Design School.

Professional Qualifications

Since 1995, Ted Johnson has served as President and Research Director of TRJ Environmental, Inc. — a consulting company specializing in exposure assessment and air quality analysis. From 1977 to 1995, he managed the Air Quality Assessment and Analysis Group in the Durham, North Carolina office of IT Air Quality Services. Mr. Johnson has served as project manager and environmental engineer on a variety of projects related to the statistical analysis of air quality data and the estimation of population exposure to air pollution. Mr. Johnson is the principal designer of two computer-based models currently used by the U.S. Environmental Protection Agency (EPA) to estimate population exposure: the Probabilistic NAAQS Exposure Model (pNEM) and the Hazardous Air Pollutant Exposure Model (HAPEM). He is currently developing versions of EPA’s state-of-the-art Air Pollution Exposure Model (APEX) applicable to CO and ozone. He has authored over 140 articles and reports on subjects relating to exposure assessment, time/activity data, and indoor air quality -- including the use of Monte Carlo techniques in exposure modeling, personal exposure monitoring, monitoring of indoor air pollution and air exchange rates, mass balance modeling, and the prediction of human ventilation rates. Mr. Johnson was cochairman of the technical program for the APCA/ASQC conference entitled Quality Assurance in Air Pollution Measurements. He is currently working with a research team under EPA STAR grant RD-83154101-0 to develop and test innovative personal monitoring technology for acquiring longitudinal time/activity data for use in exposure models.

Selected Publications

(See Publications Section for Complete Listing)

Ted Johnson. Analyses of Selected VOC Data Collected During Three Recent Field Studies that Employed Scripted Activity Methodologies, Project report prepared for the National Exposure Research Laboratory, Office of Research and Development, USEPA, under Contract 68-D-00-206, June 27, 2003.

Ted Johnson. "Recent Advances in the Estimation of Population Exposure to Mobile Source Pollutants," Journal of Exposure Analysis and Environmental Epidemiology, Volume 5, Number 4, October-December 1995.

Ted Johnson and J. Capel. A Monte Carlo Approach to Simulating Residential Occupancy Periods and Its Application to the General U.S. Population, EPA-450/3-92-011, U.S. Environmental Protection Agency, Research Triangle Park, N.C., August 1992.

Ted Johnson and Tom Long. “Determining the Frequency of Open Windows in Residences: a Pilot Study in Durham, North Carolina During Varying Temperature Conditions,” Journal of Exposure Analysis and Environmental Epidemiology, Volume 15, Number 4, pp. 329-349 (2005).

Ted Johnson, Tom Long, and Will Ollison. “Prediction of Hourly Microenvironmental Concentrations of Fine Particles Based on Measurements Obtained from the Baltimore Scripted Activity Study,” Journal of Exposure Analysis and Environmental Epidemiology, Volume 10, Number 5, September-October 2000.

Ted Johnson, J. Myers, T. Kelly, A. Wisbith, and W. Ollison. “A Pilot Study Using Scripted Ventilation Conditions to Identify Key Factors Affecting Indoor Pollutant Concentrations and Air Exchange Rate in a Residence,” Journal of Exposure Analysis and Environmental Epidemiology, Volume 14, No. 1, pp. 1 - 22 (2004).

Ted Johnson, P. J. Hakkinen, and D. A. Reckhow. “Exposure Characteristics,” In: Exposure to Contaminants in Drinking Water, edited by Steve Olin, CRC Press, 1998.

D. Shamoo, Ted Johnson, S. Trim, D. Little, W. Linn, and J. Hackney, "Activity Patterns in a Panel of Outdoor Workers Exposed to Oxidant Pollution," Journal of Exposure Analysis and Environmental Epidemiology, Volume 1, No. 4, pp. 423-438.