New Research Shows Air Quality Actually Worse Indoors in London Than Outside On The City Streets

New Research Shows Air Quality Actually Worse Indoors in London Than Outside On The City Streets

Research to be published this month by We Design For… has revealed worrying news for London residents, with the city’s indoor air quality determined to be much worse than the outdoor air quality. While government and lobbyists are concerned about air pollution on the streets, the We Design For… data paints a more worrying picture, with indoor air standards often failing to comply with World Health Organisation guidance and Building Regulations.

The study recorded air quality in a number of locations around London since September 2017. Its data shows that the indoor air quality within both public and private spaces such as commercial offices, retail spaces, residential houses and apartments is consistently poor. In many cases, it is actually worse indoors than out, meaning fresh air supplies are far from fresh – and could pose a long-term health risk.

The We Design For… research concludes that properties is Central, North London and Wycombe are exceeding particulate matter guidance limits by up to 520% and that it is unlikely that many of the buildings they have tested comply with the Building Regulations annual mean limit for NO2. . More than 60% of the buildings tested in the last year had higher levels of harmful NO2 and PM2.5 inside than out.

Building Regulations state that exposure to nitrogen dioxide (NO2) should not exceed 288 μg/m over a one-hour average, and 40 μg/m over a long-term average – with many buildings failing to satisfy these targets, the law is being broken, yet there is rarely monitoring in place to measure, record or tackle this issue.

All buildings are required by law to provide a certain level of ventilation, to help reduce the risk of damp and condensation, prevent the build-up of bacteria and remove allergens and pollutants. However, as the air being brought into homes and offices is not ‘fresh/ clean’ air, the process can become counterproductive.

Dr. Dominic Clyde-Smith, UCL and Head of Research at We Design For… said, “The test results we have been gathering over the past year show that indoor air pollution is a serious problem within our homes, offices, shops, schools and other premises that we all spend so much time in. Most interestingly our test results have highlighted that ventilation alone is not a viable solution and that recognised industry guidance regarding the control of ventilation systems and location of fresh air intakes needs updating. What we are seeing in London is conclusive evidence that the ventilation and filtration systems simply aren’t up to the task – leaving Londoners to breathe in pollutants and harmful particulates at levels that are far from safe.”

“As an industry we need to design for appropriate levels of filtration and look to reduce sources of air pollution. It is unfortunate that the failings of our government to tackle illegal air pollution have created this problem, but this is a problem that we are very capable of solving.”

Pete Carvell, Director at We Design For…said, “There has been a lot of debate recently about harmful pollution and degrading air quality. People tend to believe that the widely publicised effects of air pollution do not affect them when they are indoors; either at home or at work – they assume that the air indoors is cleaner than on the street. Our results prove that this is simply not the case and that conditions indoors are actually often worse.

“We believe that more people need to be made aware of this – our results show conclusively that urban dwellers need to be asking more questions about their indoor air quality. We needto be looking at what we can do to make indoor air quality better, just as we work to reduce outdoor air pollution.”

While improving building ventilation systems is often an expensive solution both in terms of capital investment and energy costs, there are other options to improve air quality. We Design For… offer air quality and ventilation system testing, evaluation, design and consultancy services.  They have recently developed an ‘active’ green wall product with one of the major green wall manufacturers that has been proven to remove a measurable 100% of particulate matter and NO2 from a test space during trialling.

To find out more, view a selection of the data online:

A detailed summary and report will be published on their new website at