Mapping Mobility: Utilizing Local-Knowledge-Derived Activity Space to Estimate Exposure to Ambient Air Pollution...

Area of Science:

• Environmental Health
• Public Health
• Geospatial Analysis

Background:

• Homelessness is increasing in the U.S., yet air pollution exposure for this population remains unquantified.
• Assessing environmental exposures is crucial for understanding health risks in vulnerable groups.

Purpose of the Study:

• To quantify air pollution exposure, specifically fine particulate matter (PM2.5), among individuals experiencing homelessness.
• To compare PM2.5 exposure estimates derived from local knowledge mapping with traditional monitoring methods.
• To investigate the spatial variation of PM2.5 exposure at a local scale.

Main Methods:

• Utilized local knowledge mapping to define activity spaces for 62 individuals experiencing homelessness in a semi-rural county.
• Employed satellite-derived measurements of PM2.5 to estimate annual air pollution exposure.
• Compared localized PM2.5 estimates with data from stationary monitors and point location estimates.

Main Results:

• Detected significant spatial variation in PM2.5 exposure among participants at both point and activity space levels.
• The annual median PM2.5 exposure for participants was 16.22 μg/m³, surpassing the National Air Quality Standard.
• Local knowledge mapping provided a granular view of exposure, differing from stationary monitor data.

Conclusions:

• Local knowledge mapping is a novel method for capturing mobility patterns and assessing air pollution exposure in vulnerable populations.
• Traditional stationary monitoring may lead to exposure misclassification, especially in areas with limited monitoring infrastructure.
• Findings underscore the significant air quality risks faced by individuals experiencing homelessness.