Wet bulb effect can prove fatal, caution experts

HYDERABAD: With daytime temperatures on a steady rise, experts are advising people to be cautious about the twin phenomena of the urban heat island (UHI) and the wet bulb effect.While UHI occurs when a city experiences warmer temperatures than nearby rural areas, the wet bulb effect is when a person's body fails to cool down due to a combination of high temperature and humidity, resulting in victims suffering heat stroke despite having access to shade.According to experts, the wet bulb impact can be exacerbated by UHI, which is already on a rising trend."Wet bulb effect happens when sweating becomes ineffective at removing the body's excessive heat due to a lot of moisture in the air. This results in increase in body temperature, which can lead to serious exhaustion, heatstroke, fatigue, confusion, palpitations, and other ailments. Moreover, the sudden transition that occurs when people come out of AC rooms can lead to heat-induced ailments," said Dr Dasari Anusha, senior consultant, internal medicine at AIG Hospital.Dr Anusha said the effect could lead to organ failure and even death in the absence of access to artificial cooling.According to a 2017 paper published in ScienceDirect, even healthy people with unlimited water, shade, and no physical activity can die of heatstroke after a few hours of exposure at wet bulb temperatures. While the regular temperature measures only air-temperature, a wet bulb temperature accounts for both the temperature of the air and humidity in it.Dr A Sravani, senior scientist, IMD, said rising temperatures are inducing heatwave conditions. "Urban areas are hotter due to concrete structures. Pollutants are another contributor to wet bulb impact. This instability affects cloud creation, and even a 40°C temperature makes us feel scorching heat."