Quantifying the Magnitude of Heat Microenvironments and Exposure Risk in Small Cities and Rural Communities

Extreme heat is increasingly recognized as a growing public health threat and has been identified as the leading cause of weather-related deaths in the US over the past 30 years. While much of the UHI research is focused on large metropolitan areas, there is growing recognition that northern climates and smaller communities are increasingly experiencing extreme heat events and potentially impacted by extreme heat, however they remain understudied. To address this gap, this work seeks to better understand the drivers of extreme heat microenvironments in small cities and rural communities and to understand who is potentially exposed and where across the urban to rural development continuum. The research team collected mobile transect data and fixed point observations in ten communities across the state of Vermont to characterize the magnitude and timing of the UHI signal. High resolution spatial land cover data was used to understand the influence of proximate built environment characteristics on canopy layer air temperature. To assess the potential population level exposure to extreme heat, building footprints derived from statewide lidar data were intersected with parcel polygons and address data from the statewide E911 database to generate a residential building database. The population including demographic characteristics of age, race and income were statistically assigned across single and multi-family residential housing units at the US Census block level using the 2020 US Census. High resolution impervious surface area coverage proximate to residential buildings across the state was used a proxy for potential exposure. The resulting population level exposures, analyzed on a decile basis, demonstrate that lower income and non-White residents are disproportionately exposed across the urban-rural continuum of the study area. These results highlight the need for systemic solutions to the problem of extreme heat microenvironment exposure across communities of all sizes.