Microscale urban heat variability and time-location patterns: Elevated exposure for bikers and rickshaw drivers beyond average city temperatures in megacity

Urban heat island effect creates diverse microclimates, influencing heat exposure and consequent health effects. Study measured heat exposure among delivery riders within their microclimate, comparing it with city's average temperature. We investigated how higher exposure affects work, health, and productivity of riders.

For 21 days in winter and summer, we measured heat exposure during peak hours (under sun and shade) in riders' immediate environment, at seven high-traffic routes in Karachi, Pakistan. Recorded temperature were compared with city's ambient air temperature. In-depth interviews were conducted to assess the impacts on riders' health, welfare, and productivity.

During winter, temperature was 5.0 °C higher under sun and 1.6 °C higher under shade, as compared to city average recorded temperatures. In summer temperature was 5.5 °C higher under sun and 1.8 °C higher in shade as compare to recorded city's average air temperature. Riders reported exhaustion, reduced productivity, income loss, and negative impacts on social wellbeing during hot days. For mitigation riders relied on strategies like staying hydrated and taking breaks from work under shades. Study demonstrated higher exposure to heat for riders in megacity as compare to city's recorded temperature. This led to reduced productivity and income losses, emphasizing need for urgent initiatives to safeguard riders' well-being.