What about London’s air?

15th October 2015

Air quality in London is a growing concern that now claims over 9,500 lives prematurely each year. Long-term exposure to air pollutioncan reduce a person’s life span by as much as 9 years1. Although measures are being taken to clean up the capital’s air, levels continue to rise above EU safety guidelines.

The Problem

The main offenders are fine particulate matter (PM 2.5) and nitrogen dioxide (NO2) created primarily by local diesel emissions from cars, Lorries and buses that are congesting the cities roads and streets2. Once at street level the dispersal of pollutants is made increasingly difficult due to the street canyon effect between buildings, a phenomenon that prevents polluted air from escaping immediately into the atmosphere. When combined with times of high atmospheric pressure the air at pedestrian level becomes a deadly soup of toxic fumes.

Our Research

Treebox has been working towards improving Air quality by dealing with emissions at street level nearest to the source. Committed to Greening Grey Britain the team has spent the last two years researching and trialling various methods to tackle what we believe to be a significant environmental and health issue facing our cities today, poor air quality. There has been considerable research conducted over the years indicating that plants provide clean air through dust repression and photosynthesis but our research shows this can be further enhanced, by transitioning a living wall from a passive greening solution into Active greening systems.

These systems draw polluted air into small water filled pressure chambers that then direct the air directly into plant root zones, where the micro-organisms break down harmful pollutants into less harmful particles. This process, known as Aerogation, does more than just filter the air, it purifies it over 99%. Thus removing PM 2.5, NO2 and VOCs along with unwanted odors and even pollen.

The Vision

The Air Purification Unit (APU) is a micro Active greening system that can be deployed almost anywhere for short term or permanent applications. They are powered by solar or other renewable sources and designed to last for over 10 years. Each unit can produce over 800,000L of purified air each day and make a significant improvement immediately.

Our vision is to take these to the streets and there is no better location to start than bus shelters. They are at pedestrian level, close to the emission sources and utilizing a space which is often overlooked for green infrastructure projects.

We are in process of producing a fleet of these systems, our vision is to soon see entire bus routes turned to clean air zones, that have the potential to purify millions of litres of polluted air each day, which in turn, offsets diesel emissions on any given route.

Staffordshire University is currently testing the effectiveness of the units at extracting NO2 and will be publishing results later this year.

(APU : Vauxhall Station Kiosk, London, 2015)

What about cost?

Capital cost is minimal, local authorities could contribute enough to cover installation cost whilst the private sector can sponsor the units and cover ongoing service costs. The units are designed to be leased for short and long-term deployment. If 1 in every 5 people forfeited buying one cup of coffee a month in the capitol, we’d be able to install and maintain a staggering number of units around the city. Essentially we would create over 20,0000 sqm of green space in pollution hotspots without competing for any ground space at all.

We hope London can be the face of this campaign and at the forefront of a sustainable city movement which other EU cities facing similar toxic challenges can learn from. But we need support to help bring our vision to life.

If you are interested in being involved or sponsoring an APU then email us on apu@greenlease.co


Nearly 9,500 people die each year in London because of air pollution – Environment. The Guardian. 15/07/2015.

2Over 50,000 deaths each year in the UK due to NO2 and Particulates – Sunday times 13/09/2015