Ivette Torres, Khanh Do, Andrea Delgado, Charlotte Mourad, Haofei Yu, Cesunica Ivey 

Background.
Higher air pollution emissions can be observed near rail networks, local and highway automobile corridors, and shipyards. Communities near such sources are often disproportionately exposed to emissions from these stationary and mobile sources. One such community is West San Bernardino in California, where households are feet away from the Burlington Northern Santa Fe intermodal facility and are impacted by activities that are estimated to continuously emit air pollutants due to 24/7 operation.

Objective.
This study aimed to (1) quantify the impact of personal mobility and housing characteristics on daily PM2.5 exposures and well-being for West San Bernardino community members, and (2) develop individualized resilience plans for community collaborators to support future PM2.5 exposure reduction.

Methods.
Personal PM2.5 exposures were measured for each community collaborator for seven consecutive days during three deployment periods: October 2021, January 2022, and March 2022. Indoor and ambient PM2.5 levels were also continuously measured for five households over six months using PurpleAir Classic monitors. Demographic and well-being data were collected upon recruitment and after each week of engagement, respectively.

Results.
Personal exposures in home microenvironments were highest near the railyard and decreased with distance from the railyard. Home exposures were 40% higher on average compared to non-home microenvironments. Household PM2.5 levels had a higher-than-expected average infiltration factor of 0.70, and indoor 98th percentiles across the households far exceeded a healthy level at an average of 61 μg/m3. Increasing median personal exposures were linearly correlated with worsening health conditions.

Significance.
Results suggest that surrounding land use, household building characteristics, and indoor activity all compound to worsen air pollution exposures beyond what is expected for exposures in non-industrialized areas. Findings prompt a call for stronger regulation, not only for emissions, but also for indoor air quality and zoning standards that specifically protect disproportionately impacted communities.