Environmental Exposure Assessment

Environmental Exposure Science Research

Spatial Health Lab

The primary goal of our research is to develop innovative exposure science methods by integrating advanced geospatial analysis, data science, and interdisciplinary study designs.

These methods are designed to be applied to large-scale epidemiological studies, enhancing our ability to understand the relationships between environmental exposures and human health.

Specific research projects

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World map showing nitrogen dioxide (NO2) levels.

Evaluating and Applying Google Location Data for Built Environment and Physical Activity Research

Funding: National Institutes of Environmental Health (NIEHS), R21ES031226 (PI: Hystad)

Environmental exposures are commonly estimated using spatial methods, with most epidemiological studies relying on home addresses. Passively collected smartphone location data, like Google Location History (GLH) data, may present an opportunity to integrate existing long-term time-activity data.

In this grant we collected GLH data from a subset of participants in the Washington State Twin Registry (WSTR) using a citizen science “Bring your own location data” approach. GLH included over 287 million location records from 357 participants. The map below shows GLH location data and how it can be used to assess personal environmental exposures.

GLH data is a feasible and cost-effective method for capturing retrospective time-activity patterns for large populations that presents new opportunities for environmental epidemiology. Cohort studies should consider adding GLH data collection to capture historical time-activity patterns. Privacy and Google policy changes around GLH data retention remains a concern that needs to be carefully managed when using GLH data.

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Example of street view imagery

Deep Learning of Street View Imagery to assess Urban Green Space Relationships with Mental Health:  A Twin Study

Funding: National Institutes of Environmental Health (NIEHS), R21ES029722 (PI: Hystad)

We are developing advanced computer vision models to analyze street view imagery, not only to detect and classify elements of urban green space (e.g. trees, grass) but also to predict perceptions of the built environment, such as green space quality. By integrating deep learning techniques, our models can assess both the physical attributes and subjective perceptions of green spaces, provi ding a richer understanding of green space exposure. Applying these models to the WSTR study allows us to control for genetic and familial factors, isolating the urban green space impacts on mental health outcomes.

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example of urban quality maping

Built Environment Assessment through Computer visiON (BEACON): Applying Deep Learning to Street-Level and Satellite Images to Estimate Built Environment Effects on Cardiovascular Health

Funding: National Health, Lung, and Blood Institute (NHLBI), R01HL50119 (PI: James)

The BEACON project aims to leverage advanced deep learning techniques to analyze both street-level and satellite images to assess the built environment’s impact on cardiovascular health. By using computer vision models, the project seeks to automatically classify various elements of the built environment—such as green space, walkability, and urban density—as well as urban quality measures—such as green space quality and safety — for the entire United State to link to Nurses Health cohorts.  We have developed urban quality deep learning models for urban green space quality, beauty, attractiveness, relaxing potential, safety from traffic, and safety from crime and have predicted these metrics for 120 million locations for 2008, 2012, 2016, 2020, which can facilitate new studies into how built environment composition and quality influence human health and well-being.

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A grid-based visualization showing various urban metrics over time.

TRANSIT Accountability Study: Impact of Vehicle Emission Regulations on Traffic-Related Air Pollution Exposures and Infant Health

Funding: Health Effects institute (HEI), RFA 18-1 (PI: Hystad)

In the United States, billions of dollars have been spent implementing interventions to reduce traffic-related air pollution (TRAP). These interventions are usually regulatory actions focused on reducing tailpipe emissions. However, they also include local programs to reduce traffic congestion and excess vehicle emissions, such as electronic tolls and roadway capacity improvements. Few health studies have empirically evaluated the direct impact of air pollution exposure reductions from these emission regulations and congestion reduction programs; no studies have examined infant health, an important population health outcome linked to air pollution exposures.

We applied geospatial exposure science methods to Vital Statistics data in Texas from 1996 to 2016 (n = 8.1 million recorded births) to isolate the influence of TRAP, and TRAP changes, on adverse birth outcomes.  We derived diverse environmental exposure measures for residential locations.

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An aerial view of a map with various labels and a legend.

We integrated “connected device” data into exposure models to measure vehicle congestion at the street-segment level to determine the additional effects of congestion-related air pollution on health outcomes. This is the first application of connected device data to measure population-level mobility in an environmental epidemiology study. We also developed methods to compare birth outcomes of maternal neighbors living upwind and downwind of the same high-traffic road, reducing the potential for confounding by SES and noise exposures.

Research paper highlights

Hystad, P., Amram, O., Oje, F., Larkin, A., Boakye, K.A., Avery, A.R., Gebremedhin, A.H., & Duncan, G.E. (2022). Bring Your Own Location Data: Use of Google Smartphone Location History Data for Environmental Health Research. Environmental Health Perspectives, 130. DOI:10.1289/EHP10829

 

 

Larkin, A., Krishna, A., Chen, L., Amram, O., Avery, A.R., Duncan, G.E., & Hystad, P. (2022). Measuring and modelling perceptions of the built environment for epidemiological research using crowd-sourcing and image-based deep learning models. Journal of Exposure Science & Environmental Epidemiology, 32, 892 - 899. DOI:10.1038/s41370-022-00489-8

 

 

Larkin, A., Willis, M.D., Harris, L., Ritz, B., Hill, E.L., & Hystad, P. (2024). High Traffic Roads and Adverse Birth Outcomes: Comparing Births Upwind and Downwind of the Same Road. American journal of epidemiology. DOI:10.1093/aje/kwae120

 

 

Willis, M.D., Schrank, D.L., Xu, C., Harris, L., Ritz, B., Hill, E.L., & Hystad, P. (2022). A population-based cohort study of traffic congestion and infant growth using connected vehicle data. Science Advances, 8. DOI:10.1126/sciadv.abp8281

 

GitHub repositories

Matching_HEI_4970

This github repository contains the scripts used to compare birth outcomes between maternal neighbors upwind/downwind of the same high-traffic road.

NationalStreetViewPerceptions

This github repository contains datasets and methods to create national US surfaces of street view perceptions. Google Street View (GSV) images are not included due to user liscence restrictions. However, those who are interested can download GSV images using the unique image ids and headings provided in the datasets.

GSV_NDVI_Comparison

The Python and C++ files in this folder were used to download Google Street View (GSV) images from the GSV API, download NDVI estimates from Google Earth Engine, and screen GSV images for green pixels and calculate greenpixel summary statistics. Files are organized into folders, with one folder for each task described above. Note that several external modules, keys and tokens are needed. Requirements vary by task and are described within each script.

Perceptions_MTurk

Create standardized methodology for capturing perceptions of street view locations using Google Street View and Amazon Mechanical Turk.

PDXNoiseSurface

This repo contains scripts and accompanying documentation used to create outdoor noise surface estimates (LEQ) for Portland, OR at 10m resolution.

Past research projects

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exposure framework

Technology and environmental exposure assessment

Assessing individual exposures over long time-periods has been a major challenge in environmental epidemiology, but new technologies and related advances in data science hold great potential to improve personalized environmental exposure estimates. We are developing new exposure assessment methods and applying these to a variety of epidemiological studies.

Global model of traffic air pollution

Geographic Information Systems (GIS) offer unprecedented opportunity to conduct spatial exposure assessment. We have developed a global model for traffic air pollution using a land-use regression prediction method that estimates nitrogen dioxide levels at a 100x100 meter resolution for every location in the world. These data are available at Resources and Data.

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streetview image

Street-view image-based exposure methods

The emergence of ubiquitous geo-referenced imagery (e.g. Google Street View imagery), combined with advances in image processing using deep learning algorithms, offers unprecedented opportunity for assessing built environment exposures. We have several ongoing studies that are developing new built environment feature measures and applying to large epidemiology studies.

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Perceptions of the built environment

Quantifying perceptions of the built environment is central to understanding how different built environment features influence health. For example, if a park is not viewed as safe it will not be used.  We are leveraging crowd-sourced data on perceptions of urban beauty, safety, and liveliness to better understand the relationships between these perceptions and built environment features.