Jill Johnston, PhD

Jill Johnston, PhD is an Assistant Professor and Director of Community Engagement in the Division of Environmental Health at University of Southern California. She is an exposure scientist and environmental epidemiologist with long-standing relationships with environmental justice communities.  Her research focuses on addressing unequal exposures to harmful contaminants that affect the health of working poor and communities of color.  She engages in collaborations with grassroots organizations to conduct community-engaged action-oriented research on environmental health disparities.  She has fostered strong partnerships and trust with local and regional organizations to build innovative community engagement and participatory research activities on environmental health and science.  Dr. Johnston received her PhD in environmental sciences and engineering from the University of North Carolina at Chapel Hill, where she studied hazardous waste sites and industrial animal production.  


Dayane is a first-generation college graduate and received her B.S. in Public Health from CSULA. She joined Dr. Johnston’s team in 2017 and worked on a project involving communities living near a lead-smelting factory in Los Angeles. Currently, she works in the Children’s AIRE Study assisting with field work as well as project coordination. Her research interests include working with vulnerable populations/EJ communities and learning about the effects that air pollution has on the human body.


Mariann Tobar is currently a third year undergraduate student double majoring in Biological Sciences and East Asian Language and Culture (EALC). Her primary interest in this research project is to gain a better understanding of the socio-economic impacts in vulnerable communities in regard to environmental justice and access to healthcare. Her secondary research interest is utilizing Epidemiology to evaluate public health issues in local populations and cancer biology.


Karen Mejia, Research Coordinator with USC Children’s AIRE Study since 2019. Growing up in the Imperial Valley and seeing first hand the disadvantage of some of its residents has given her the drive to work with organizations that aim to improve people’s lives. She’s been involved with community engagement programs beginning in 2012 when she helped create a mobile health clinic to provide screening for those not covered by health insurance.  Now with the AIRE Study she has an opportunity to help bring awareness to children’s health development to both participants and their parents.

Yoshira Ornelas Van Horne

Yoshi is the first Latina to receive a PhD in Environmental Health Sciences from the Mel and Enid Zuckerman School of Public Health at the University of Arizona. As part of her dissertation, she worked with the Diné communities impacted by the Gold King Mine Spill to develop a community-based risk assessment and collaborated with multiple partners to ensure the dissemination of culturally appropriate results report back materials. Her research combines community engagement with exposure assessment to address environmental health concerns.


Amanda brings a background in Environmental Management and Sustainability, Integrated Science and Technology, and Environmental Engineering. Her work includes data management and content development around air toxics, low cost sensors, land use, and urban oil drilling. As a bilingual Spanish study coordinator, Amanda currently leads the BELLA and Health and Neighborhood Air pollution community-based research projects.


Kate Vavra-Musser is a PhD Candidate in the Population, Health, and Place program with the USC Spatial Sciences Institute, Department of Preventative Medicine, and Department of Sociology.  Her research interests focus on environmental health and environmental justice.  Dr. Jill Johnston is one of Kate’s two doctoral co-advisors – along with Dr. An-Min Wu – and supports her research on soil lead contamination in East Los Angeles and its relationship to human health.  Kate previously received an MS in Global Health and Environment in 2015 from the University of California, Berkeley and BS in Biology with a specialization in Ecology and Evolution in 2009 from the University of Chicago.  She is originally from Southwest Michigan.

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