Human Exposure Modeling - Air Pollutants Exposure Model

APEX/TRIM.Expo _Inhalation

The Air Pollutants Exposure Model (APEX) is a PC-based model that was derived from the probabilistic NAAQS Exposure Model for carbon monoxide (pNEM/CO). Reports describing prior OAQPS applications of the pNEM to carbon monoxide and ozone are available. APEX serves as the human inhalation exposure model within the Total Risk Integrated Methodology (TRIM) model framework. See TRIM - General Information page for historical information about TRIM and peer review of the TRIM and TRIM.Expo approach.

APEX is intended to be applied at the local, urban, or consolidated metropolitan area scale and currently only addresses inhalation exposures. The model simulates the movement of individuals through time and space and their exposure to the given pollutant in various microenvironments (e.g., outdoors, indoors residence, in-vehicle). The user may choose the number and types of microenvironments to be included, select the time period of interest, use either monitored ambient air quality data or values provided from dispersion or other modeling runs, and use either a mass balance approach or an empirical ratio-based (factor) approach to estimate indoor and/or in-vehicle concentrations. Results of the APEX simulations are provided as hourly and summary exposure and/or dose estimates, depending on the application, for each individual included in the simulation as well as summary statistics for the population modeled.

Three different versions of TRIM.Expo_Inhalation (also known as APEX) are currently available: APEX 3.3, for use within TRIM, and two other versions of APEX (APEX 5.2 and 4.5), for stand alone use.

• Download Model

• User's Guides for versions 5.2, 4.5,  and 3.X

• Example Applications 

• Peer Review and Publications

• Presentations at Scientific Meetings and Conferences

• Other Supporting Documentation