Whitest-ever paint could help cool heating Earth, study shows - The Guardian

The whitest-ever paint has been produced by academic researchers, with the aim of boosting the cooling of buildings and tackling the climate crisis.

The new paint reflects 98% of sunlight as well as radiating infrared heat through the atmosphere into space.

First, barium sulphate was used as the pigment which, unlike conventional titanium dioxide pigment, does not absorb UV light.

The barium sulphate paint enables surfaces to be below the ambient air temperature, even in direct sunlight, because it reflects so much of the sun’s light and also radiates infrared heat at a wavelength that is not absorbed by air.

The researchers said the ultra-white paint uses a standard acrylic solvent and could be manufactured like conventional paint.

Lukas Schertel, a light-scattering expert at the University of Cambridge, UK, who was not part of the research team, said: “Using paint for cooling is not new but has still a high potential to improve our society, as it is widely used.

Schertel said the high concentration of pigment in the paint and the relatively thick layers used raised questions of cost: “Pigment is the main cost in paint.” Ruan said his team hoped to optimise the paint so it can be used in thinner layers, perhaps by using new materials, so it will be easier to apply and lower cost

Parnell said a comparison of the carbon dioxide emitted by the mining of barium sulphate with the emissions saved from lower air conditioning use would be needed to fully assess the new paint