Improving Heat-Related Health Outcomes in an Urban Environment with Science-Based Policy

Abstract

Abstract:We use the Northeast US Urban Climate Archipelago as a case study to explore three key limitations of planning and policy initiatives to mitigate extreme urban heat. These limitations are: (1) a lack of understanding of spatial considerations-for example, how nearby urban areas interact, affecting, and being affected by, implementation of such policies; (2) an emphasis on air temperature reduction that neglects assessments of other important meteorological parameters, such as humidity, mixing heights, and urban wind fields; and (3) too narrow of a temporal focus-either time of day, season, or current vs. future climates. Additionally, the absence of a direct policy/planning linkage between heat mitigation goals and actual human health outcomes, in general, leads to solutions that only indirectly address the underlying problems. These issues are explored through several related atmospheric modeling case studies that reveal the complexities of designing effective urban heat mitigation strategies. We conclude with recommendations regarding how policy-makers can optimize the performance of their urban heat mitigation policies and programs. This optimization starts with a thorough understanding of the actual end-point goals of these policies, and concludes with the careful integration of scientific knowledge into the development of location-specific strategies that recognize and address the limitations discussed herein.

Air-Temperature Response to Neighborhood-Scale Variations in Albedo and Canopy Cover in the Real World: Fine-Resolution Meteorological Modeling and Mobile Temperature Observations in the Los Angeles Climate Archipelago

“…In Figure 9a-i, observed air temperature ( • C) from mobile transects is plotted on the vertical axis against grid-level (neighborhood-scale) albedo (ALB) or canopy cover (VEG), where ALB and VEG are each computed via Equations (1) and (2). This analysis is for the downtown area defined by the rectangle on the right in Figure 1.…”

“…Characterization of urban heat and its causes, such as land-surface properties, is an important first step towards designing countermeasures [1,2]. Understanding the correlation between urban heat and variations in land-cover and physical properties of the urban surface is also critical in understanding how future changes in land use can inadvertently impact urban heat, e.g., the heat island effect, and, hence, its mitigation.…”

Summer average urban-rural surface temperature differences do not indicate the need for urban heat reduction

“…Unwanted effects due to high temperatures in cities, including human heat discomfort, building energy consumption, heat-related mortality and morbidity, etc., are a function of the thermal, radiative, moisture, and hydrodynamic conditions of the urban atmosphere and their daily evolution (i.e., including the background climate)they are not due to differences between summer averaged urban and rural Ts as M19 strongly imply. The aim must, therefore, be to reduce the negative effects of urban heat, and not urban-rural temperature differences 16,17 .…”

Physical geography contributes

“…Urban climatology provides an additional example of the integration of the four understandings. The field of urban climatology has as its foundation the environmental physics of built surfaces (e.g., heat absorption and emission) but extends to human impacts and hazards, such as the health consequences of urban climates (Arnfield, 2003; Sailor et al, 2016). Urban climatology is also rooted in spatio-temporal modeling that integrates the atmosphere, hydrosphere, lithosphere, and biosphere (Shaffer et al, 2015).…”