Collection of Time Activity Data to Support Exposure Assessment: Protocol for a Systematic Evidence Map.

Background: Time Activity Data (TAD) describe the timing, duration, and/or frequency of human activities. Given that activity dictates the rate of contact a person has with an environmental agent, activity data can be used to derive rigorous estimates of exposure. TAD has been used to support exposure estimation in a variety of contexts, although there has been no systematic characterization of how TAD has been collected for environmental health applications.

Objectives: We propose a systematic evidence map protocol in pursuit of describing the body of environmental health literature that collects TAD to estimate exposure to chemical, biological, and physical agents. Our work proposes a novel definition for TAD, identifies studies collecting TAD, compiles a list of terms used to describe TAD, and summarizes how this data has been collected to estimate various environmental exposures.

Methods: This protocol details the proposed search strategy, which targets environmental exposure studies that collect information on human activities and when they occur, using Population-Exposure-Method (PEM) criteria. From each study, we will extract data that will be categorized according to a codebook that we develop. In order to refine and improve our methodology iteratively, we will use reflexive journaling to ensure that the data collected are coded and summarized appropriately.

Discussion: We will produce an open-source database and a systematic evidence map depicting the patterns, trends, and gaps existing in the current body of environmental health literature that collects TAD to estimate exposure to environmental agents. Researchers will be able to use this evidence map to assess prominent themes and may reference the database to identify specific studies collecting TAD, which can inform future environmental health research.