Indoor Air Quality (IAQ) is an important issue for architects, specifiers and building managers in the UK.
Materials manufacturers will soon have to publish data on what contribution their materials make to IAQ,
following what is now becoming standard practice in Scandinavia. It is a critical issue when considering
ventilation. This is a short note drawing attention to the issues. The subject is a huge one, justifying a full
issue of the Digest in the future.
After a great deal of interest in ‘Sick Building Syndrome’21 in the mass media in the late 1980s, public
interest appears to have declined somewhat, though the fashion for solid wooden floors instead of carpets is
a result of a partial understanding of such issues among consumers. However the problem has not gone
away. As most of us spend 90% of our lives inside buildings, certainly in colder climates, the internal air
that we breathe is laced with a huge cocktail of chemicals and ‘natural;’ pollutants that can seriously affect
our health. Good ventilation is a key factor in reducing the impact of indoor pollution, but reducing the
chemicals at source is the most effective solution for green designers. Specifying green and ‘natural’
materials with low toxicity would appear to be one of the most effective ways, when coupled with an
effective ventilation strategy, of ensuring good IAQ.
Surprisingly there is little medical research into the impact of IAQ on health. Bodies such as the Medical
Research Council and the National Asthma Campaign do not appear to have given it sufficiently high
priority. A great deal of medical opinion links allergic and respiratory problems to genetic rather than
environmental causes. When environmental causes are blamed, these are largely attributed to external
pollution such as from traffic rather than IAQ. There are also powerful vested interests in the pharmaceuticals
world to promote the sales of inhalers and anti allergy remedies, one of the most lucrative sources of profits
for the drug companies.
It is possible that the lack of sufficient medical evidence has been one of the reasons why IAQ has not
been accorded a high priority in the construction industry. However research at the University of
Strathclyde in Glasgow is investigating the links between domestic environments and the increasing
prevalence of asthma.22 They attribute many of the problems to the reduction of ventilation rates, higher
levels of humidity and the air tightness of modern constructions. Recently an American authority in the
field, Hal Levin said, at the International Indoor Air Quality Conference in Edinburgh, that the weight of
scientific evidence demonstrates clearly that indoor pollution (rather than external) is one the main
influences on our health.23 A large amount of scientific work in the IAQ field is slowly beginning to
influence building regulations and manufacturer of building products, particularly in more progressive
countries such as Sweden, Denmark and the Netherlands.24 The International IAQ conference in Edinburgh
in August 1999 had over 600 scientific papers, but it was stated that there has been a failure to transfer
much of this knowledge to a wider audience. Much of the research has been pre-occupied with developing
methods of measurement and analysis (which are crucial) rather than the effects of indoor air pollution on
building occupants. This failure to communicate was recognised at IAQ 99 and a workshop specifically
discussed linking IAQ research with the wider sustainable construction movement.
The main sources of Indoor Air pollution are;
building materials, paints, varnishes etc., technical equipment (printers, photocopiers etc.), cleaning
fluids, polishes etc., common products that are used indoors, body effluents, ambient air quality, including
pollution from outside and smoking.
Standards do exist for acceptable levels of some of these pollutants but they do not always take into
account the problems of people who are allergic or hypersensitive to certain materials. However building
codes in various countries tend to focus mostly on CO2, CO and NO2 and pay less attention to the levels of volatile organic compounds.25 This can largely be attributed to pressure from commercial interests that do
not want to see further controls on toxic emissions from their products.
While levels of pollution from tobacco smoke and cleaning materials can be controlled, VOCs and other
chemicals are concentrated into the actual fabric of buildings and this means removing the use of such
materials at the specification stage. Emission levels can vary widely depending on the finishes in buildings
and at different times in the life of a building. Studies at the Building Research Establishment have
identified 254 Volatile organic compounds emitted from building materials in the first year of the life of four
newly built houses and 71 during the second year.26 Other listings show a much larger range of toxic
materials found in buildings and clearly these will vary depending on the materials used in construction.27
Paints and flooring materials are the main sources, but other products can also be significant.28 Higher
temperatures, during the summer or from winter heating, lead to higher emission levels and while the
highest release is in the early life of a building many chemicals can linger for much longer. A wide range
of chemicals which are suspected of causing health problems including Toluene, Naphthalene, Xylenes,
Formaldehyde, Lindane and many more can be detected in conventional houses. Many of these chemicals
have been referred to in past issues of the Green Building Digest, particularly the issues on Paints for
Joinery, Adhesives, Interior Decoration, timber preservatives and so on and more information on them can
be found in the relevant digest. Many people are also sensitive to natural pathogens such as pollen, dust
mites and mould. It is important to ensure that the remedies to this do not introduce new VOCs into the
indoor environment. Also many anti fungal and mould treatments use biocides which in themselves are
toxic to humans.
Many of the environmental assessment systems for buildings did not include IAQ and toxic emissions in
their categorisation though the BRE Environmental Standard, Homes for a Greener World,29 introduced
measurements of Formaldehyde, Wood preservatives and Paint with lead in 1995 and has been largely
ignored. Much tougher standards are likely to be introduced in the future when the new BRE environmental
profiling system30 is widely adopted and ventilation standards in the building regulations will eventually be
related to the effect of materials on our health.
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