TRJ Environmental

Recent Projects

Risk-Distance Lookup Tables for the EPA Air Toxic Control Rule Applicable to Benzene Emitted by Gasoline Distribution Area Sources.

Ted Johnson modified SimRisk (a probabilistic exposure/risk model developed previously by TRJ Environmental) for application to three model gasoline distribution facilities. SimRisk converted estimates of modeled ambient benzene concentrations at receptor points surrounding each facility to corresponding estimates of lifetime exposure and associated cancer risk. These estimates were statistically analyzed to develop lookup tables of risk vs. distance for the EPA Air Toxic Control Rule applicable to gasoline distribution area sources.

A Personal Monitoring System Employing a Newly-Developed Continuous Ozone Monitor.

TRJ Environmental developed a personal monitoring system consisting of a portable continuous ozone monitor, a DVD camcorder, a GPS system, a heart-rate monitor, an accelerometer, and a time/activity diary. The system was field-tested by Tom Long, who employed the system in a variety of microenvironments and exercise regimes according to a prepared activity script. Ted Johnson statistically compared the ozone exposure measurements made by the personal ozone monitor with ozone concentrations measured simultaneously by a nearby fixed-site monitor in Raleigh, North Carolina.

Minute-by-Minute Estimation of Lung Function Decrements Due to Ozone Exposure.

Ted Johnson and Jim Capel developed a probabilistic algorithm that calculates lung function decrements on a minute-by-minute basis according to the time sequence of ozone exposure and exercise level. The algorithm was installed in APEX-Ozone, EPA’s current population exposure model for ozone, and tested using a wide range of exposure and activity scenarios. The algorithm contains probabilistic components that realistically simulate the subject-to-subject variability observed by Dr. William McDonnell in recent clinical findings.