Stay informed with free updatesSimply sign up to the UK property myFT Digest -- delivered directly to your inbox.In London’s Mayfair, the lofty neoclassical staircase of 66 Grosvenor Street has been freshly painted a sophisticated grey. The lick of paint has more to it than just a modern colour palette. The experimental paint job also embeds compounds designed to attract and break down pollutants in the air, explained Andy Creamer, who has overseen a recent overhaul of the building to bring the 300-year-old Georgian town house, now used as offices, up...