Modeling the Effects of Urban Design on Emergency Medical Response Calls during Extreme Heat Events in Toronto, Canada

Abstract

Urban residents are at risk of health-related illness during extreme heat events but the dangers are not equal in all parts of a city. Previous studies have found a relationship between physical characteristics of neighborhoods and the number of emergency medical response (EMR) calls. We used a human energy budget model to test the effects of landscape modifications that are designed to cool the environment on the expected number of EMR calls in two neighborhoods in Toronto, Canada during extreme heat events. The cooling design strategies reduced the energy overload on people by approximately 20-30 W m^-2, resulting in an estimated 40-50% reduction in heat-related ambulance calls. These findings advance current understanding of the relationship between the urban landscape and human health and suggest straightforward design strategies to positively influence urban heat-health.

Keywords: energy budget modeling; landscape architecture; urban design.

Figure A1

Existing conditions of Downtown.

Figure A2

Microclimatic redesign of Downtown.

Figure A3

Existing conditions of Scarborough.

Figure A4

Microclimatic redesign of Scarborough.

Figure 1

Locations of Census Tracts (CTs) selected for re-design.

Figure 2

Mean daily city-wide baseline energy budget (bEB) from 11h00 to 18h00 by period (consolidated across all years). Data are mean ± SD. Letters “a” and “b” are between-period comparisons, where different letters indicate statistical significance.

Figure 3

Typical summertime wind directions during sunny conditions at Lester B. Pearson Int’l A weather station for the years 1955–1970. Data are in percentage of time during summer months. Source: {Environment Canada—Atmospheric Environment Services, 1970} [31].

Figure 4

Mean daily (11h00–18h00) pEB on EHE days calculated using the master plans of Downtown and Scarborough before (Existing conditions, grey bars) and after (Proposed conditions, white bars) “cooling” re-design. Data are mean ± SD. Letters “a” and “b” represent comparisons between Existing and Proposed designs within CT, where different letters indicate p < 0.0005 for master plans of Existing vs. Proposed conditions (within-CT, by paired t-test).