The "LivingBox", launched this week, is a collaboration with Public Space Jam and artist Andrea Tyrimos.
Treebox, which specialises in green walls and roofs, has installed a lush, evergreen living wall enveloping one side of the phone box. The wall actively cleans the air through "aerogation" technology, which draws polluted air through the roots of plants in the wall where it is purified by soil microbes.
Aerogation was created by US company AgroSci, and is licensed to Treebox for European use. Treebox owner Armando Raish hopes to roll out Air Pollution Units in polluted spots and bus stops across London.
Each 2sqm green wall can process one million litres of air per day. It has been shown to purify air to 99 per cent purity in an indoor setting; tests are being carried out at Staffordshire University to determine how effective the walls are at extracting nitrogen dioxide - London's worst street pollutant - from the air.
Tyrimos spent 30 days painting creeping plants over the booth at 79 Southampton Row representing the need for a cleaner, greener city. Members of the public who peer into the box can see the constellation of stars that would be seen from London if the air was cleaner.