Comparing Outdoor, Indoor, and Personal PM Levels in an Environmental Justice Community in California’s Central Valley

JESSICA TRYNER, Grace Kuiper, Sherry WeMott, Bonnie Young, Luis Hernandez Ramirez, John Volckens, Sheryl Magzamen, Colorado State University

     Abstract Number: 488
     Working Group: Identifying and Addressing Disparate Health and Social Impacts of Exposure to Aerosols and Other Contaminants across Continents, Communities, and Microenvironments

Abstract
People living in the United States (U.S.) typically spend >90% of their time indoors, mostly in their homes. As a result, both outdoor and indoor pollution sources contribute to personal exposure to particulate matter (PM); however, most data on PM pollution are collected for outdoor ambient conditions. Furthermore, factors that can enhance or mitigate exposure to pollutants outside and inside a person’s home are linked to environmental justice (EJ) issues associated with the history of racially- and ethnically-discriminatory land use and housing policies in the U.S. In this study, we measured 24-h in-home concentrations of and personal exposures to PM_2.5 and PM₁₀ for 47 adults living in 27 households within a designated EJ community in California’s Central Valley. We also surveyed participants about characteristics of their home as well as possible sources of pollution outside and inside the home. Personal exposures to PM_2.5 tended to exceed outdoor concentrations (median personal = 15.3 μg m^-3; median outdoor = 8.9 μg m^-3; median personal − outdoor difference = 11.7 μg m^-3), and personal exposures to PM₁₀ tended to be lower than outdoor concentrations (median personal = 52.4 μg m^-3; median outdoor = 80.5 μg m^-3; median personal − outdoor difference = -35.1 μg m^-3). Personal exposures were only weakly correlated with outdoor concentrations measured by regulatory and community monitors (Spearman correlation = 0.27 for PM_2.5 and -0.19 for PM₁₀), but personal exposures were more strongly correlated with in-home concentrations (Spearman correlation = 0.61 for PM_2.5 and 0.59 for PM₁₀). Prior studies in other U.S. communities have reported median personal and outdoor PM_2.5 levels both lower and higher than those measured here. We will discuss variables associated with personal PM exposure as well as the need for more widespread indoor and personal measurements.