Environmental Street Audits and Black Carbon Measurements in Vietnamese Immigrant Communities

Background: The Vietnamese population has grown significantly in California and has clustered in geographic areas with potential disproportionate exposures to environmental stressors. No studies to date have focused on environmental exposures in this immigrant population.

Objective: To characterize neighborhood-level environmental hazards in Vietnamese communities in California to inform environmental health research.

Methods: We engaged Vietnamese community members in the Alameda, Marin, Orange, and Santa Clara regions to conduct community audits in neighborhoods where they lived and worked. Audits included surveys of observational neighborhood characteristics, Photovoice documentary and real-time personal black carbon (BC) aerosol monitors.

Results: Traffic-related air pollution, litter, smoking, and neighborhood safety were identified as major environmental concerns. Audits in Alameda County reported a higher percentage of metal bars on windows and litter relative to other counties. Orange County had the highest percentage of audit segments with idling trucks (20.8%) and tobacco ads (8.3%), as well as average 5-minute truck count (9.8). The mean BC concentration across all four regions was 1.8 μg/m³, and ranged from 1.7 μg/m³ in Santa Clara County to 2.0 μg/m³ in Orange County. When analyzed at smaller geographic units (neighborhoods), there was more variation across the regions, with Alameda County having the highest neighborhood concentration (7.7 μg/m³).

Conclusions: Our results showed higher mean BC concentrations at the regional and neighborhood levels compared with the statewide concentration (0.737 μg/m³). Community members collected quantitative and qualitative data including real-time BC data. The audit process helped to initiate dialogue about environmental health issues in the Vietnamese communities.