Cool it

2019-03-06 06:20:11

By Michael Fitzpatrick ROADS that trap water like a baby’s nappy could help keep the sweltering streets of Tokyo cool, say the city’s engineers. In the countryside, the air is cooled by water evaporating from leaves and soil, and the vegetation also provides shade, keeping down temperatures. But like many cities, built-up Tokyo doesn’t have much vegetation and as a result suffers from the “urban heat island” effect. In July, the city can be a few degrees hotter than the surrounding countryside—often exceeding 30 °C. The materials used to build roofs,