Source apportionment of fine particulate matter (PM_2.5) personal exposures: findings from the Household Air Pollution Intervention Network (HAPIN) study in rural Guatemala

Background: Source apportionment is a method that reconstructs sources of pollution from monitored values. The identification of these sources is important to develop interventions and other strategies to improve environmental quality. Objective: This study aimed to identify and quantify potential sources that contribute to fine particulate matter (PM_2.5) personal exposures in a cohort of pregnant women participating in a fuel-cooking intervention trial in Guatemala. Methods: We estimated the PM_2.5 and black carbon (BC) concentrations from 629 polytetrafluoroethylene (PTFE) filter samples using gravimetric and transmittance analyses, and we analyzed inorganic elements using energy dispersive X-ray fluorescence (ED-XRF). The filters correspond to personal exposure samples collected with the Enhanced Children’s MicroPEM™ (ECM) from pregnant women who cook using biomass or liquefied petroleum gas (LPG) fuels within the Household Air Pollution Intervention Network (HAPIN) randomized-controlled trial in rural Jalapa, Guatemala. We used the U.S. Environmental Protection Agency’s (EPA) Positive Matrix Factorization (PMF) model to identify the potential sources. Results: A four-factor source apportionment model was derived from PMF. The potential sources and their relative contributions to PM_2.5 mass were identified as: biomass burning ( ~ 69.6%), fossil fuels (22%), crustal, and other soil ( ~ 4% each). When categorizing our samples by study group, baseline (155 µg/m³; 95% CI: 129.7, 180.2) and post-intervention control (127.2 µg/m³; 95% CI: 114.7, 139.7) samples had the highest amount of PM_2.5 mass (49.7% and 40.7%, respectively) compared to 9.6% (29.9 µg/m³; 95% CI: 27.2, 32.7) from intervention samples. Significance: We identified biomass burning, fossil fuel burning, crustal and other soil as sources of PM_2.5 pollution in rural Jalapa, Guatemala. These findings pave the road for future source apportionment studies in this region and highlight the importance of source characterization to implement interventions to reduce PM_2.5 emissions. (Figure presented.) Impact: We identified four potential sources of PM_2.5 in rural Jalapa, Guatemala, based on personal exposure samples from pregnant women participating in the HAPIN trial. Biomass and fossil fuel burning are the sources with the highest contributions, followed by crustal and other soil. The findings of this study highlight the potential to prioritize emissions reduction efforts in rural Guatemala through the implementation of specific interventions based on the derived sources of pollution.