Objective: Oxidative potential (OP) is a metric, that quantifies the ability of particulate matter (PM) to induce oxidative stress in humans and cause health outcomes. Although people spend the largest proportion of their time in residences, our understanding of exposure to OP and PM constituents in this critical environment is limited. Here, we attempt to address this research gap by quantifying the OP and chemical composition of PM collected from diverse residential environments and evaluating the effects of residential characteristics in discerning the residential PM and OP exposures.
Methods: Here, we collected PM samples from 22 homes in the Champaign-Urbana region (CUR) and characterized their composition and OP using dithiothreitol (DTT) assay. Residential characteristics were collected using questionnaires from each participant.
Results: The median OP of residential PM was 185.90 pmol/(min.m3), which is comparable with the values reported for ambient PM2.5 in CUR. Exploratory exposure assessment revealed higher OP exposure in residences compared to outdoors, due to larger proportion of time spent indoors. Water soluble organic carbon, Cu, and Mn were mainly driving OP, aligning with past findings on ambient PM2.5. Both particle mass concentrations (PMC) and OP increased with increasing window-opening frequency or decreasing floor area, indicating the effect of building characteristics on PM/OP exposures. The median PMC and OP of residences using gas stoves were 72% and 42% higher than those using electric stoves, respectively. Similarly, scented candle usage also resulted in a 71% and 34% increase in the median PMC and OP respectively, signifying the importance of indoor-origin PM in determining residential exposure.
Conclusions: Collectively, these findings reveal that residential characteristics play a significant role in determining PMC and OP exposure indoors and emphasize the need for studies with larger cohort sizes to reliably estimate residential exposures to toxic PM, as a function of built environment’s characteristics.
Speaker Bio: P. S. Ganesh Subramanian is a Ph.D. student in the Department of Civil and Environmental Engineering at the University of Illinois Urbana-Champaign. He received his bachelor’s and master’s degree in Earth and Environmental Sciences from the Indian Institute of Science. His current area of research is evaluating the particulate matter induced health effects, using acellular surrogates of toxicity, in indoor environments. His hobbies include reading, cycling, gardening and yoga.