The APU is installed at Mace's The Avenue site, a retail and office development on Tottenham Court Road. The street is a busy shopping destination but is also a pollution hotspot.
Air purification units (APUs) are vertical garden spaces that integrate technology and plants to remove pollutants from the air, a process called phytoremediation. New "aerogation" technology created by US company AgroSci speeds up the rate at which the green wall processes pollutants by up to 200 times, allowing an area of just 4m2 to churn out up to 2 million litres of purified air every 24 hours.
The APU has been installed as part of a trial that will last until July 2017.
Andrew Kinsey, head of sustainability for Mace Construction, said: "It's great to be able to pilot and integrate this innovative idea into our working environment.
"Not only will it help to improve the air quality for our workers and the public, but it also sends out a strong message of what can be done to make a difference and address the key issue of pollution. Hopefully in the future we can integrate more of these units at other sites."