Climate Week Best Campaign 2012

Facts & Research

Research from Imperial College and Kings College London shows that closing the door reduces airborne pollution in shops by a third

Independent research has demonstrated that closing the door results in a one-third reduction in the levels of three airborne pollutants - PM2.5, black carbon and NO2 - during working hours.

This is important because:

  • There are serious health risks associated with high levels of air pollution - a particular problem in London and across UK cities due to diesel vehicle emissions(1)
  • Diesel vehicle exhaust is classified by the World Health Organisation as a Group 1 carcinogen
  • Air pollution caused 29,000 deaths across the UK in 2008(2), and many times that amount of related hospital admissions
  • These included 4,300 deaths in London(3). By comparison, 4,000 deaths in the Great Smog of 1952 led to radical action and the Clean Air Act of 1956
  • The damaging components of airborne pollution are now largely invisible, odourless and tasteless, leaving people unaware of their presence
  • Airborne particulates (PM2.5 and PM10) from diesel emissions are small enough to cross the lung lining and enter the blood stream, to affect not only the lungs but the heart, brain and other organs. NO2 (gas) in air pollution is similarly hazardous to health (1,2,4)

About the study

  • Independent research, carried out over a six week period in summer 2014 on Regent Street, London
  • Conducted by the MRC-PHE Centre for Environment & Health, which is a partnership between Imperial College and King's College London
  • Originally proposed by the Close the Door campaign
For more details, see the overview of the research.

(1) Ostro, B. (2003), Outdoor Air Pollution, Environmental Burdon of Disease Series, No.5, World Health Organisation, Geneva, p5
(2) COMEAP (2010) Committee on the Medical Effects of Air Pollution p1
(3) Miller, B. (2010), Report on estimation of mortality impacts of particulate air pollution in London, IOM Consulting Report, Edinburgh, p7
(4) Miller, Shaw, Langrish (2012) Oxidative Stress and the Cardiovascular Effects of Air Pollution



Cambridge University research proves that closing a shop door in winter saves up to 50% in energy usage and carbon emissions

The research, commissioned by the campaign, proves exactly how much energy is wasted by shops leaving their doors open with the heating on.

The research found that closing a shop door when heating is being used:

  • Reduces energy usage by up to 50%
  • Cuts a shop’s annual CO2 emissions by up to 10 tonnes of CO2, equivalent to 3 return London Hong Kong flights (1)
  • Assists with mandatory national 34% reduction in carbon emissions
  • Enhances comfort of staff and customers, maintaining temperature at Chartered Institution of Building Services Engineers (CIBSE) recommended levels all day, even when outside temperature plummets
  • Maintains energy use at a standard low level
  • Enables heating to be shut off long before the end of the day without affecting internal temperatures
  • Stops need for so-called “air curtains” over the door – among the greatest wasters of energy: a single one consumes 24 kWh per day. This is equivalent to emitting 91 kg CO2 per week, or more emissions than a return Glasgow London coach trip

The research found no conclusive evidence that footfall or transactions were affected by closing the shop door.(2)

About the study

  • Conducted over the winter of 2009/10 in Cambridge
  • Research by the Glass and Façade Technology Group, Department of Engineering, University of Cambridge
  • Commissioned by the Close the Door Campaign who were funded by The Esmee Fairburn Foundation.

For the original research see the summary presentation and report.

(1) Based on an average of 150 days a year being cold enough for shops to need heating in Cambridge
(2) The study approximated footfall by measuring door openings when the door was closed, which is an underestimate as groups are counted as one door opening, and no consistent trend was found when compared with beam-interruption footfall data for open doors. To accurately compare transactions would require a larger sample and/or would need to take into account effects specific to the days measured e.g. day of week, weather, public events or offers in competitive shops.