Extreme heat is now the leading cause of weather-related deaths in the United States. As temperatures rise and climate change intensifies, cities are particularly vulnerable due to the Urban Heat Island (UHI) effect, where metropolitan areas are significantly hotter than surrounding rural regions. Understanding this phenomenon is important for public health, urban planning, and building climate resilience as more and more people are moving into the cities.

The UHI effect is driven by:

• Heat-absorbing materials like asphalt and concrete.
• Tall buildings that trap heat and restrict airflow.
• Lack of vegetation, which typically provides cooling through shade and evaporation.

Dr. T. R. Oke's research on UHI highlights that larger cities experience a more pronounced effect due to their size and density. The heat that builds up in cities, particularly at night, forms a "heat bubble," which poses serious health risks to urban populations.

Health Risks of the UHI Effect

Dr. Clifford Mitchell, Director at the Maryland Department of Health, has warned about the increased risk of heat-related illnesses like heatstroke and exhaustion, which can be fatal if not treated. He notes that populations most at-risk—children, the elderly, and those with pre-existing conditions—face compounded threats from rising urban temperatures. In addition, hot urban areas often suffer from poor air quality, which exacerbates respiratory issues, especially among vulnerable populations.

Heatwaves are predicted to become more frequent and intense with climate change, making cities, already affected by UHI, even more dangerous. Dr. Mitchell has highlighted the importance of public health preparedness, especially in addressing heat-related bacterial illnesses.

Dr. Scott Curtis, from The Citadel, conducted a study using wet bulb globe temperature devices and thermal imaging with the help of the students and the local community and concluded that certain urban surfaces, like pavements, should be treated with special coatings. These coatings can reduce pollution, rejuvenate materials, and extend the life of pavements while mitigating heat absorption.

Cooling Strategies

While the UHI effect presents challenges, some strategies can help cool cities:

• Green spaces: Parks and urban forests can cool cities by providing shade and promoting evaporation.
• Reflective materials: Using heat-reflective construction materials for pavements and roofs reduces heat absorption.
• Better building design: Improved cooling, ventilation, and insulation systems can protect urban populations from heat stress.
• Tree planting: Urban trees improve air quality and reduce temperatures by offering shade and facilitating evapotranspiration.

By incorporating these strategies into sustainable urban planning, cities can become more resilient to rising temperatures. Urbanization may lead to the UHI effect, but with smart interventions, we can mitigate its worst impacts. The key to success lies in collaboration between public health experts like Dr. Mitchell and climate scientists such as Dr. Curtis, working alongside urban planners to create heat-resilient communities.

Future generations can enjoy safer and healthier urban environments if we recognize and address the UHI effect today.

Sources:

1. Heaviside, C., Macintyre, H., & Vardoulakis, S. (2017). The urban heat island: Implications for health in a changing environment. Current Environmental Health Reports, 4(3), 296-305. https://doi.org/10.1007/s40572-017-0140-1
2. McGregor, G. R., & Vanos, J. K. (2018). Heat: A primer for public health researchers. Public Health, 161, 138-146. https://doi.org/10.1016/j.puhe.2018.08.002
3. Oke, T. R. (1973). City size and the urban heat island. Atmospheric Environment, 7(8), 769-779. https://doi.org/10.1016/0004-6981(73)90140-6