Evaluating Cooling Adaptation Benefits for Outdoor Workers under Climate Change-Induced Extreme Heat

With the intensification of climate change, the frequency and severity of extreme heat events are increasing, posing significantly elevated heat-related risks to outdoor workers. This study adopts the Heat Index (HI), a commonly used indicator for assessing heat risk among construction workers, and integrates future climate projections derived from AR6 TaiESM1-WRF, which is one of the latest dynamically downscaled climate products developed in Taiwan (Lee, W.-L et al., 2020), to evaluate the effectiveness of two long-term adaptation strategies: work schedule adjustment and prefabrication methods.

For work schedule adjustment, strategies such as starting work earlier, extending midday breaks, delaying finishing times, and implementing nighttime construction are considered to reduce exposure to high-temperature conditions. July is selected as a representative month to calculate the number of hours during which the Heat Index exceeds Level 3 (which is considered equivalent to Level 4 under solar exposure according to Taiwan’s occupational safety regulations). The analysis further compares the variations in heat exposure under baseline, +2°C, and +3°C global warming scenarios across different work schedule arrangements.

Regarding prefabrication, construction tasks traditionally performed outdoors—such as concrete pouring, rebar tying, and mechanical and electrical installations—are relocated to indoor factory settings. This transition effectively reduces the duration of outdoor work under high-temperature conditions. Using a standard work schedule (08:00–17:00, including a one-hour lunch break), this study calculates the monthly hours exceeding the heat threshold throughout the year and estimates the reduction in heat exposure risk when outdoor construction periods are shortened by one month.

The results indicate that work schedule adjustments can effectively avoid peak heat exposure periods, while prefabrication reduces outdoor exposure at the source. Both strategies demonstrate significant cooling adaptation benefits. The findings provide valuable insights for improving occupational safety regulations and informing future climate adaptation policies.