ADB: Heat Stress, Air Pollution Risk, and Population Exposure in Asian Countries
SDG 3: Good Health and Well-being | SDG 10: Reduced Inequalities | SDG 11: Sustainable Cities and Communities | SDG 13: Climate Action
Ministry of Environment, Forest and Climate Change (MoEFCC) | Ministry of Health and Family Welfare (MoHFW) | NITI Aayog
The ADB Economics Working Paper titled Heat Stress, Air Pollution Risk, and Population Exposure: Evidence from Selected Asian Countries examines the rising and unequal exposure to heat stress and ambient air pollution across Bangladesh, Indonesia, Pakistan, Thailand, and Viet Nam. Using the Universal Thermal Climate Index (UTCI) and satellite-based PM2.5 estimates, the study identifies critical “climate hotspots” where these two hazards frequently overlap. The findings indicate that population exposure is highly stratified, with significant variations based on residential location, occupational roles, and socioeconomic status.
Demographic Vulnerabilities and Environmental Stratification
The research highlights that marginalized populations often reside in high-risk areas, facing disproportionate cumulative exposure to harmful conditions:
Gendered Risks: In countries like Viet Nam and Thailand, a higher proportion of women face risks from both hazards compared to men, often influenced by their roles in the informal labor sector or housework.
Age-Specific Impacts: Children and older adults are consistently identified as the most vulnerable groups. In Bangladesh, older populations are disproportionately exposed to extreme heat and pollution, while in Thailand, employed children face high risks.
Labor Force Status: Employment status is a major determinant of exposure. While those outside the formal labor force (unemployed or inactive) often face greater heat burdens, dense metropolitan growth attracts large numbers of workers to urban “pollution-island” hubs.
Country-Specific Correlation Patterns
The interaction between temperature and pollution varies significantly by geography:
Bangladesh: Exhibits a strong negative correlation, with air quality worsening significantly during colder months due to temperature inversions trapping pollutants.
Pakistan: Demonstrates a positive correlation, where certain districts experience simultaneous shocks of extreme heat and high PM2.5 levels, often influenced by dust storms and dry heat.
Indonesia: Shows no clear seasonality in PM2.5 levels or strong correlations between the two hazards.
Thailand: The correlation varies depending on the temperature measure used, with air pollution levels remaining relatively consistent throughout the year.
Viet Nam: Highest pollution months coincide with specific temperature ranges (27°C to 35°C), often linked to monsoonal inversion and agricultural burning.
What is the “Universal Thermal Climate Index” (UTCI) in climate risk assessment? The UTCI is a comprehensive bioclimatic index designed to assess human physiological comfort by integrating multiple atmospheric parameters, including air temperature, humidity, wind speed, and solar radiation. Unlike simple temperature readings, it captures “perceived thermal stress,” ranging from moderate discomfort (26°C to 32°C) to extreme heat stress (above 46°C), providing a more accurate measure of the actual health and productivity risks faced by population.
Policy Relevance
The study’s findings on the Indo-Gangetic Plain’s seasonal PM2.5 patterns—mirrored in Bangladesh—provide a direct blueprint for India to refine its National Programme on Climate Change and Human Health (NPCCHH). Identifying stratified exposure through the double-dual-distributional (DDD) framework allows municipal authorities to design targeted “Heat Action Plans” that protect informal workers and the urban poor from urban “pollution-island” effects. Furthermore, the varying correlation between heat and pollution underscores the need for integrated surveillance systems to provide dual early warnings for compounded health shocks.
Follow the full report here: Heat Stress, Air Pollution Risk, and Population Exposure: Evidence from Selected Asian Countries