US EPA

This document provides a summary of the technical meeting on greenspace (GS) and cumulative risk assessment convened May 4−5, 2015 in Cincinnati, OH, by the U.S. Environmental Protection Agency (EPA) Office of Research and Development (ORD) National Center for Environmental Assessment (NCEA). This science meeting explored how methods and measures used to assess GS could contribute to cumulative risk assessments (CRA) (and vice versa).

Meeting Objective

The main objectives of the meeting were to (1) identify how GS is being described and its impacts assessed for human health and (2) gain insights from GS assessments for cumulative risk assessment applications. To realize these objectives, the EPA convened GS experts and practitioners from multiple disciplines to participate in joint presentations and facilitated discussions. The presentations and discussions were topically organized by exposure and health, and framed by questions developed by the organizers.

Approach

The meeting was structured to focus on approaches and tools for estimating GS exposure, and potential risks and benefits of GS exposure for human health and insights for CRA applications. Meeting participants shared duties in presenting relevant research on agenda sub-topics and leading group discussions.

Findings

Both GS assessments and CRAs are relatively new approaches for characterizing both the health benefits and risks associated with complex environmental exposures. While existing evidence supports that GS effects are primarily beneficial for human health, GS assessments strongly depend on the factors specific to the places and populations of interest, which can differently influence the duration, frequency, and type of human exposure to various types and quantities of GS. Quantification and qualification of dose-response relationships related to GS exposure is limited for GS assessments, largely due to uncertainty around GS exposure measures and the mechanisms of action between GS engagement and human health outcomes.

Background Information

Current evidence suggests that GS benefits public health directly by providing a dynamic space for exercise, social interactions, and other behaviors that could lower psychological stress and improve mood. Additional benefits of exposure to GS appear to include improved cognition, attention restoration, and improved immune function. Although data are limited, GS might mitigate or attenuate health outcomes brought on by psychological stress (e.g., cardiovascular disease). GS exposures may also be associated with a few adverse effects, notably respiratory and dermal irritation related to allergens. Approaches to GS measurement and conceptualization of multiple and interacting influences on human health continue to evolve.

CRA is a relatively recent and evolving field of risk analysis. CRAs are designed to characterize and quantify, to the extent possible, the combined risks to human health or the environment from exposures to multiple stressors, including chemical, physical, biological, and psychosocial stressors (U.S. EPA, 2003). The similarity between analyses of GS and CRA led EPA to believe that GS analyses could inform methods to evaluate nonchemical stressors and services within this type of risk assessment.

This document provides a summary of the technical meeting on greenspace and cumulative risk assessment (GS CRA) convened May 4−5, 2015 in Cincinnati, OH, by the U.S. Environmental Protection Agency (EPA) Office of Research and Development (ORD) National Center for Environmental Assessment (NCEA). This report highlights the presentations, discussions, and practical suggestions offered by the meeting participants; however, the report does not present consensus opinions of the meeting participants. The report was prepared by Argonne National Laboratory, supported by the EPA under an interagency agreement through U.S. Department of Energy contract DEAC02 06CH11357, in collaboration with the EPA ORD NCEA Organizing Committee and the GS CRA Technical Work Group. The meeting participants reviewed and refined this report before final review and clearance by the EPA.

Gernes, R., R. Hertzberg, M. MacDonell, G. Rice, J. Wright, G. Beresin, T. Miller, J. Africa, G. Donovan, J. Hipp, P. Hystad, L. Jackson, M. Kondo, Y. Michael, R. Mitchell, M. Nieuwenhuijsen, P. Ryan, W. Sullivan, AND M. Annerstedt van den Bosch. Estimating Greenspace Exposure and Benefits For Cumulative Risk Assessment Applications (Summary Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-16/025, 2016.