URBAN HEAT ISLAND (UHI), AIR POLLUTION, AND HUMAN HEALTH: A REVIEW

Abstract

Urbanization is accelerating globally, with more than 56% of the world’s population currently living in 
urban areas, a figure projected to reach nearly 70% by 2050. UHI is characterized by elevated urban 
temperatures relative to surrounding rural areas due to the prevalence of impervious surfaces, reduced 
vegetation cover, and anthropogenic heat emissions from buildings, transportation, and industry. This 
review focuses on the causal mechanisms linking UHI and urban air pollution and their combined impacts 
on human health. UHI alters atmospheric dynamics, often contributing to thermal inversions that trap 
pollutants near the ground, increasing both their concentration and duration of exposure. The health 
impacts associated with co-exposure to heat and pollution are multifaceted and severe. Epidemiological 
evidence shows increased rates of cardiovascular and respiratory disease, renal failure, heatstroke, 
neurological impairment, and mental health disorders. Vulnerable populations, including children, the 
elderly, low-income groups, and those with preexisting health conditions, face disproportionate risks due 
to limited access to cooling resources, medical care, and clean environments. These challenges are 
especially acute in cities in developing countries, where infrastructure and governance capacities are 
often insufficient to meet rising demands. Urban greening, including trees, parks, and green roofs, 
reflective building materials, permeable pavements, sustainable transportation systems, and low-emission 
zones, public health interventions such as heat action plans, early warning systems, and community 
outreach programs can all provide a panacea to reducing the tripartite effects of urban heat island, air 
pollution on human health.