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Monday, July 6, 2015
Poor air quality is killing more people in the UK than smoking and alcohol combined; accounting for 29,000 premature deaths every year, according to Public Health England.
The recent heatwave has focused attention on the effects of outdoor pollutants and has exacerbated already serious problems with transport emissions, but there is also a major problem INSIDE buildings.
Poor indoor air quality (IAQ) may be responsible for the loss of over 200,000 ‘healthy life years’ in Britain, according to a new study published by the Finnish National Institute for Health & Welfare(THL). Its research appears to prove the link between exposure to indoor pollutants and cardiovascular disease, as well as a number of other health hazards leading to reduced life expectancy.
57% of the total burden relates to cardiovascular diseases, 23% to lung cancer, 12% to asthma and the remaining 8% relates to other respiratory conditions, the Institute reported, adding that changing the way buildings are ventilated could reduce the overall impact of indoor air pollution by as much as 38%.
Making this link to the health impact on building occupants is timely because of the UK government’s current legal tangle with the European Union over our appalling record on air quality.
The UK has been in breach of Europe’s air pollution limits since 2010, leading the European Commission and environmental lawyers to launch separate legal actions that carry fines of up to £300m a year. Lawyers acting for the European Commission said the UK's failure to act on air quality was “perhaps the longest running infringement of EU law in history”.
Just as in the 70s and 80s when government health advisers started to recognise the need to act over the impact of smoking on cancer and heart disease, so today we see growing evidence of the health impact of airborne particles and other gaseous pollutants.
However, there still seems to be a perception that air brought into a building via ‘natural’ ventilation is, in some way, organic – and therefore wholesome; while anything processed by a ventilation fan or through a filter is the equivalent of genetically modified crops and to be treated with suspicion.
This myth really needs to be dispelled, particularly in the light of the UK’s newly acquired status as the dirty air champion of Europe. The growing risk of outdoor pollutants entering buildings is adding to the problem posed by the various threats that already exist indoors including volatile organic compounds (VOCs) found in carpets, paints etc.
People spend more than 90% of their lives indoors; often in sedentary occupations and with the windows open because the building is overheated.
The situation has been exacerbated over the last two decades by the drive to improve the energy efficiency of buildings, which has involved making them more airtight. Sealing up buildings puts pressure on ventilation systems to dilute rising levels of CO2 and replenish oxygen while simultaneously trying to prevent the rising number of harmful external pollutants from finding their way inside. This is very hard to achieve ‘naturally’.
It is not surprising that the European Commission is putting pressure on the UK. Its Environment Committee has revealed that poor air quality is responsible for 360,000 premature deaths across the continent. Many airborne particles are precisely the right size for inhalation into lungs and the body has no way of removing these invaders so they go on to cause damage and disease to vital organs.
The government admits that Greater London, the West Midlands and West Yorkshire will remain in breach of EU air quality law until beyond 2030 – an extraordinary admission, but one that proves the depth and seriousness of this issue. Recently London’s Oxford Street was labelled ‘the most polluted street in the world’ due to extraordinarily high levels of traffic pollution. New studies have linked nitrogen oxide (NO2), which is often caused by petrol and diesel emissions, to higher rates of lung cancer and heart failure.
This threat continues to grow because government policy was focused on reducing CO2 emissions leading to the promotion of diesel vehicles. The World Health Organisation (WHO) has declared diesel particulates as a Class 1 carcinogen.
In Central London the concentration of diesel and nitrogen oxide (NOx) is about three times the WHO recommended level. This figure was only made public following a challenge from theCampaign for Clean Air, which estimates that London suffers a 20% increase in mortality rates as a result.
If you live on a busy arterial road in London you are continually exposed to two or three times more harmful inhalable particulates than the WHO warning level and it is also slowly starting to dawn on people that if you have a problem with outside air pollution; you are likely to have a problem inside the nearby buildings.
There are a lot of shops and offices on Oxford Street with their doors and windows open, for example, and in thousands of schools around the country, children are finding it increasingly difficult to concentrate in their polluted classrooms. Inside hospitals, most of which are located in busy urban areas, patients are at the mercy of harmful airborne particulates in poorly ventilated wards.
The Healthvent EU research project, carried out by the Technical University of Denmark, reported that almost two thirds of the burden of disease due to IAQ was from pollutants coming into the building.
For good health and productivity the air needs to be about 20-24degC with a relative humidity (RH) of about 40-60%. The ventilation system needs to dilute CO2 levels and replace oxygen – it’s a very fine balance and, because of the heavy focus on reducing energy use, many building managers are using ‘natural’ methods as much as possible and getting the balance wrong.
Air tight building envelopes are a good way of saving money and keeping out external pollutants, but opening windows is not a good idea if you don’t know the level of pollutants in the outside air – and you will undermine the energy saving strategy.
It is very hard to get the right balance of temperature, humidity and air quality through ‘natural’ means alone and it is essential to invest in proper maintenance of air handling units and ductwork hygiene to keep particulate levels under control.
A well-sealed building envelope and effective filtration of incoming supply air can reduce particle penetration by 78%, according to a range of studies. This shows that testing a building for airtightness is just as much a health issue as part of an energy saving strategy.
The recently revised BS EN 15780 standard also provides recommended inspection time periods for air systems to improve monitoring and the B&ES Guide to Good Practice for ventilation system hygiene (TR/19) provides contractors with clear guidelines in line with this standard.
B&ES has also set up an Indoor Air Quality Strategy Team to gather as much information as possible about this hugely important area and help building engineering services firms advise their clients. We have plenty of technical expertise and a range of solutions, but find ourselves continually preaching to the converted. The big task is communicating to the wider world that buildings are not always safe havens from pollution – just as they don’t always successfully exclude the environment when it is too hot or too cold outside.
As the country’s air pollution crisis intensifies, we have a national platform to promote better understanding of the need for high quality building ventilation accompanied by proper, planned maintenance.
There is nothing ‘wholesome’ or even ‘natural’ about urban air. It is, in no way, organic and, just as it took time for scientists to establish that diesel engines were not the carbon answer; so it will take time for people to recognise the facts about indoor air quality and the need for urgent action.
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