Quantifying localized heatwave impact on mortality: a multi-country modeling study in the Asia-Pacific region

Area of Science:

• Environmental Health
• Epidemiology
• Public Health

Background:

• Global heatwaves pose significant public health risks.
• Existing definitions lack region-specific health outcomes and acclimatization data.
• This limits the applicability of heatwave warnings across diverse populations and climates.

Purpose of the Study:

• To develop and assess a novel health-based heatwave definition.
• To evaluate the impact of localized heatwaves on mortality.
• To compare the proposed definition with existing methods.

Main Methods:

• Utilized daily mortality and weather data from 25 cities in Australia, China, South Korea, and Thailand.
• Developed a health-based excess heat factor (HEHF) using a tiered health risk-based (THR) approach.
• Incorporated a region-specific temperature threshold and an acclimatization index into the HEHF calculation.

Main Results:

• The HEHF demonstrated a higher association with increased mortality risk compared to other definitions.
• It identified localized, time-varying temperature thresholds and captured continuous mortality risk patterns.
• The HEHF attributed a larger proportion of deaths to heatwaves across all studied countries.

Conclusions:

• The developed HEHF framework provides a generalizable and health-based method for defining localized heatwaves.
• This approach enhances the assessment and comparison of heatwave health impacts across different regions and climates.
• The findings underscore the importance of localized and acclimatization-aware definitions for effective heatwave risk management.