Extreme heat in urban areas can have deleterious consequences on human health and can lead to increases in building cooling energy use. These impacts are projected to become more significant in the future due to ongoing urbanization, population densification, and global climate change. The aim of this research is to answer the question, what are the most effective urban heat mitigation strategies for the populations that are most vulnerable to extreme heat? The analysis will focus on neighborhoods in Los Angeles, CA that contain populations that are especially physically and financially vulnerable to increasing extreme heat: (1) the elderly, (2) those without air conditioning, and (3) those of low socioeconomic status that cannot afford increased energy costs.

The research will develop a multi-scale coupled modeling framework that resolves regional-scale meteorology, micro-scale meteorology, and building energy flows. Neighborhoods in Los Angeles with vulnerable populations will be identified using parcel-level GIS datasets of population age, income, and access to air-conditioning. The heat mitigation strategies that will be assessed include solar reflective rooftops and pavements, and increased use of street-level and rooftop urban vegetation. These mitigation strategies will be assessed for impacts on (a) outdoor and indoor air temperatures, (b) human thermal comfort, heat stress, and heat-related mortality, (c) indoor thermal conditions for representative buildings without air conditioning, and (d) air-conditioning energy use for representative buildings with air conditioning. Model performance for each element of the model will be thoroughly evaluated by comparing to observations. The multi-scale model and methods for targeting vulnerable populations will be applicable to other cities worldwide in future work. Results from the project will provide targeted solutions to help vulnerable populations deal with extreme heat. Solutions will be communicated to local policy makers, utilities, and other stakeholders, all of whom the PIs have already-established relationships, to provide pathways for implementation. Discoveries will also be communicated to middle and high school students in areas with vulnerable populations through outreach programs at University of Southern California (USC). The PI will work with teachers through USC's Research Experience for Teachers program, with the goal of designing curriculum and research focused lessons that teach students about the fundamental physics describing extreme heat mitigation. Additionally, the PI will teach a demonstration focused lesson in participating teacher's classrooms to excite future young scientists and engineers to follow careers in STEM. A simple website will be created summarizing research outcomes and providing practical solutions for mitigating extreme heat.