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Indian slums receive 'cool roofs" to combat extreme heat

Over the past two months, hundreds of roofs have been coated with a white reflective coating in informal settlements in western Gujarat. This is to keep the inhabitants cool as the hot season approaches.

This effort involves 400 Ahmedabad households as part of a scientific study to determine how indoor heat affects people's health, and their economic outcome in developing countries.

Aditi Bunker is an epidemiologist from the University of Heidelberg, Switzerland, who leads the project. The Wellcome Trust, based in the UK, is funding the project.

The thing that should have protected them actually increases their exposure to heat.

Ahmedabad, which has experienced temperatures exceeding 46 C (115 F), in recent years, has been affected by climate change.

Residents who are involved in the project such as Nehal Bhil have noticed an improvement. The slum has over 2,000 homes, the majority of which are one-room, airless dwellings.

"My fridge doesn't heat any more, and my house feels cooler." My electricity bill has gone down and I'm sleeping better," said Bhil after his roof was painted.

According to a study published in 2022 in the journal Environmental Research Letters, the likelihood of heatwaves occurring around the globe has increased by nearly threefold.

Bunker's team can prevent the sun's rays from being absorbed by painting the roofs white with highly reflective pigments like titanium dioxide.

Bunker stated that "in many of these homes with low socioeconomic status, there is nothing to stop heat transfer from coming down. There's no barrier insulation on the roof."

Arti Chunara, who was to join Bunker's experimental group, said that she would cover the roof of her house with plastic sheets before joining Bunker.

She and her family would sit outside most days of the day. They would only go inside for a couple of hours if the heat was too much.

Scientists will collect data on health and indoor environments from both residents who live under a cool roofing system and those who don't.

The study also includes Burkina Faso and Mexico, as well as the island of Niue, in the South Pacific. These sites cover a wide range of climates and building materials.

Bunker stated that early results of the Burkina Faso study show that cool roofing reduced indoor temperatures by 1.2 C for tin and mud roofed homes and 1.7 C for tin roofed homes over a period of two years. This, in turn, lowered heart rates in residents. Reporting by Gloria Dickie, Amit Dave, and Shilpa jamkhandikar, in Mumbai, with editing by Barbara Lewis.

(source: Reuters)