Indoor Air Quality and Health in New Zealand’s traditional Homes

  • YEAR
    Leardini, Paola
    2010 Conference Papers


ABSTRACT: Sustainable design consists of principles and practices of architecture that protect
environmental quality and human health, reducing environmental impacts resulting from construction
activities. Considering that in New Zealand approximately 15% of the adult population and 20% of
children under the age of 15 are affected by asthma, the ongoing attempt to introduce sustainable
principles in New Zealand’s architecture appears questionable, as Indoor Air Quality (IAQ) and the
related aspect of health have been poorly considered so far. A major step towards sustainability will be
the retrofitting of the existing building stock, in order to meet new energy efficiency standards while
providing a healthier indoor environment by reducing the risk of allergies and asthma.

Allergies in New Zealand have become a serious health problem with considerable social and
economic impact. Especially the indoor environment of residential buildings plays a major role in the
increasing numbers of allergies and airways infections. Many new and renovated homes have been
designed and built with low quality insulation and heating systems, and a lack of adequate ventilation.
Furthermore, the energy performance upgrade of the existing building stock, ongoing since 1978, has
changed the buildings’ physical behaviour, generating new and unexpected problems. Badly
constructed houses are difficult and expensive to heat: the consequent inadequate thermal comfort in
homes, associated with poor ventilation, leads to growth of moulds, with health consequences.

This paper examines the indoor air pollution in relation to construction details, insulation level,
ventilation and humidity. It also addresses moisture damages caused by damp housing. The specific
influence of poor IAQ on health in general and possible risks of developing allergies in particular is
identified. The lack of information about IAQ in New Zealand’s buildings is addressed by discussing
preventative actions, advice how problems can be proactively avoided and practical recommendation
for the refurbishment of specific building typologies. As in New Zealand practice there are currently no
methods available to simulate the process of moisture transport within building components in relation
to the indoor climate, a calculative assessment of thermal and hygric processes in the external wall
assemble is introduced by using the simplified Glaser Method and the computer programme WUFI
(Wärme und Feuchte instationär). That allows producing realistic calculations of the transient heat and
moisture transport in building components under natural conditions


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