Using time-resolved monitor wearing data to study the effect of clean cooking interventions on personal air pollution exposures

Background: Personal monitoring can estimate individuals’ exposures to environmental pollutants; however, accuracy depends on consistent monitor wearing, which is under evaluated. Objective: To study the association between device wearing and personal air pollution exposure. Methods: Using personal device accelerometry data collected in the context of a randomized cooking intervention in Ghana with three study arms (control, improved biomass, and liquified petroleum gas (LPG) arms; N = 1414), we account for device wearing to infer parameters of PM_2.5 and CO exposure. Results: Device wearing was positively associated with exposure in the control and improved biomass arms, but weakly in the LPG arm. Inferred community-level air pollution was similar across study arms (~45 μg/m³). The estimated direct contribution of individuals’ cooking to PM_2.5 exposure was 64 μg/m³ for the control arm, 74 μg/m³ for improved biomass, and 6 μg/m³ for LPG. Arm-specific average PM_2.5 exposure at near-maximum wearing was significantly lower in the LPG arm as compared to the improved biomass and control arms. Analysis of personal CO exposure mirrored PM_2.5 results. Conclusions: Personal monitor wearing was positively associated with average air pollution exposure, emphasizing the importance of high device wearing during monitoring periods and directly assessing device wearing for each deployment. Significance: We demonstrate that personal monitor wearing data can be used to refine exposure estimates and infer unobserved parameters related to the timing and source of environmental exposures. Impact statements: In a cookstove trial among pregnant women, time-resolved personal air pollution device wearing data were used to refine exposure estimates and infer unobserved exposure parameters, including community-level air pollution, the direct contribution of cooking to personal exposure, and the effect of clean cooking interventions on personal exposure. For example, in the control arm, while average 48 h personal PM_2.5 exposure was 77 μg/m³, average predicted exposure at near-maximum daytime device wearing was 108 μg/m³ and 48 μg/m³ at zero daytime device wearing. Wearing-corrected average 48 h personal PM_2.5 exposures were 50% lower in the LPG arm than the control and improved biomass and inferred direct cooking contributions to personal PM_2.5 from LPG were 90% lower than the other arms. Our recommendation is that studies assessing personal exposures should examine the direct association between device wearing and estimated mean personal exposure.