Mapping Heat Vulnerability and Heat Risk for Neighborhood Health Risk Management in Urban Environment? Challenges and Opportunities.

Abstract

Purpose of review: Heat vulnerability mapping (or heat risk mapping) is commonly used as a cost-effective tool to assess neighborhood health burdens for policy development and implementations. Some local governments have adopted this strategy to develop community action plans to cope with an increasing threat from heat exposure. However, various data/methods for mapping have yielded inconsistent results. For a compact city with high population density, issues from generic mapping techniques would become more apparent due to its complexity of social/environmental structures.

Recent findings: We explored the similarities/differences in existing heat vulnerability mapping approaches. Previous models (1) failed to characterize extreme heat variations (e.g. days with different temperature extremes, difference between single hot days and prolonged heat events); (2) generally lacked a validation of associations between mapping results and various health outcomes (e.g. only relying on mortality data for validation but no validation of morbidities or clinical visits); (3) had a low ability to incorporate spatiotemporal variability of demographic patterns (e.g. difference in daytime/nighttime population patterns due to daily mobility); (4) were unable to adopt perceived heat exposure (e.g. Universal Thermal Climate Index); and (5) did not measure heat vulnerability at street-/building-levels even though 3-dimensional urban forms exist across major cities. Additionally, most applications (including those from local governments) were developed from a top-down perspective without a participatory design. A location-specific, evidence-based framework based on various exposure patterns and health outcomes with bottom-up strategies for implementations is needed for minimizing bias from "one-size-fits-all" strategies for action plans across high-density cities.