Returning results to participants of environmental exposure studies has become more common in recent years. Despite evidence of benefits for study participants, there are challenges in communicating results to people with limited resources or capacity to mitigate chemical exposures. We interviewed N = 54 participants and compared exposure report-back conducted in 2010-2013 across three susceptible study populations: 1) low-income pregnant individuals in the Chemicals in Our Bodies (CIOB) study; 2) the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) cohort; and 3) early childhood educators (ECE). Report-back differed between the cross-sectional studies (CIOB and ECE), which offered an opportunity to consult with research staff by phone or email, and the prospective cohort study (CHAMACOS), which allowed for participants to discuss individual and group-level results directly with researchers at a community meeting. Participants in all three studies were motivated to participate by children's health and wanted more information about health implications and exposure reduction strategies, with cost and limited resources cited as common barriers to change. We observed overall positive experiences with report-back across studies, with improved environmental health literacy and constructive learning experiences that were most evident in CHAMACOS. While many noted individual actions they had made or intended to make to reduce exposures, CHAMACOS participants were more likely to mention systems-level changes achieved through actions such as contacting decision-makers and raising community awareness. Our findings suggest that researchers may have a unique opportunity to support environmental health literacy and informed action at both the individual and community or policy levels through long-term study engagement, various forms of direct consultation with study participants, and thoughtful report-back methods that leverage existing tools and are sensitive to barriers faced by specific study populations. This work informs best practices for communicating chemical exposure results among sensitive or highly exposed communities.

The San Joaquin Valley in California has some of the nation’s worst air quality. Health effects from elevated outdoor air pollution may be compounded by poor indoor air quality due to use of certain consumer products or individual activities. The BiomSPHERE study measured air pollution-related urinary exposure biomarkers in residents of Stockton and Fresno, California. Urine samples were collected from 64 adult–child pairs in 2023. Metabolites of four polycyclic aromatic hydrocarbons (PAHs) and five volatile organic compounds (VOCs) were measured in urine. Questionnaires were administered to collect information on demographics and potential exposure sources. Metabolites of all PAHs (fluorene, naphthalene, phenanthrene, and pyrene) and four VOCs (acrolein, acrylonitrile, crotonaldehyde, and propylene oxide) were detected in >85% of the samples. 2-Hydroxynaphthalene (2-NAP) was the only PAH metabolite that had higher concentrations in BiomSPHERE adults and children compared with nationally representative levels reported by the U.S. National Health and Nutrition Examination Survey (NHANES). Concentrations of 2-NAP were significantly correlated (p < 0.05) between adults and children, suggesting a common exposure source. Concentrations of 2-NAP were also significantly higher among Hispanic/Latino participants and among participants who recently used cleaning products, air fresheners, and scented personal care products (p < 0.05). For non-smoking adults, metabolites of the VOCs acrolein, acrylonitrile, and propylene oxide were significantly higher in BiomSPHERE compared with NHANES. Further research is needed to identify the sources of elevated 2-NAP and VOC urinary metabolite concentrations.