# Beyond Residence: A Mobility-based Approach for Improved Evaluation of Human Exposure to Environmental Hazards

## TL;DR

This study shows that considering human mobility improves the accuracy of environmental hazard exposure assessments, revealing hidden risks for people living outside high-hazard areas.

## Contribution

The study introduces a mobility-based index to better evaluate environmental hazard exposure beyond residential locations.

## Key findings

- Neglecting mobility can lead to over 10% underestimation of environmental hazard exposures.
- Millions of people experience 5 to 10% of daily activities in high-exposure zones despite living in perceived safe areas.
- Poor and ethnic minority residents face disproportionate exposure to multiple environmental hazards.

## Abstract

Standard environmental hazard exposure
assessment methods have
been primarily based on residential places, neglecting individuals’
hazard exposures due to activities outside home neighborhood and underestimating
peoples’ overall hazard exposures. To address this limitation,
this study proposes a novel mobility-based index for the hazard exposure
evaluation. Using large-scale human mobility data, we quantify the
extent of population dwell time in high environmental hazard places
in 239 US counties for three environmental hazards. We explore how
human mobility extends the reach of environmental hazards and leads
to the emergence of latent exposure for populations living outside
high-hazard areas. Notably, neglect of mobility can lead to over 10%
underestimation of hazard exposures. The interplay of spatial clustering
in high-hazard regions and human movement trends creates “environmental
hazard traps.” Poor and ethnic minority residents disproportionately
face multiple types of environmental hazards. This data-driven evidence
supports the severity of these injustices. We also studied latent
exposure arising from visits outside residents’ home areas,
revealing millions of the population having 5 to 10% of daily activities
occur in high-exposure zones. Despite living in perceived safe areas,
human mobility could expose millions of residents to different hazards.
These findings provide crucial insights for targeted policies to mitigate
these severe environmental injustices.

This study
reveals the importance of including individuals’
mobility for the accurate assessment of hazard exposure (i.e., air
pollution, toxic sites, and heat).