Dampness and Mould - WHO guidelines for indoor air quality - PRWeb

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1. Introduction
1.1 Background
Problems of indoor air quality are recognized as important risk factors for human
health in both low-income and middle- and high-income countries. Indoor
air is important also because populations spend a substantial fraction of
time within buildings. In residences, day-care centres, retirement homes and
other special environments, indoor air pollution affects population groups that
are particularly vulnerable due to their health status or age. Microbial pollution
involves hundreds of species of bacteria and fungi that grow indoors when sufficient
moisture is available. Exposure to microbial contaminants is clinically associated
with respiratory symptoms, allergies, asthma and immunological reactions.
Indoor air plays a special role as a health determinant, and management of indoor
air quality requires approaches that differ from those used for outdoor air.
For these reasons, the working group preparing the global update of the WHO
air quality guidelines (WHO Regional Office for Europe, 2006a) recommended
that WHO also prepare guidelines for indoor air quality. This is in line with the
recommendations of an earlier WHO working group that formulated The right
to healthy indoor air and, in particular, with its Principle 6, which states that “Under
the principle of accountability, all relevant organizations should establish explicit
criteria for evaluating and assessing building air quality and its impact on
the health of the population and on the environment” (WHO Regional Office for
Europe, 2000a).
The subsequent working group meeting in Bonn in October 2006 acknowledged
the applicability of the existing WHO guidelines for air quality (WHO Regional
Office for Europe, 2000b, 2006a) to indoor air and identified a number of
chemical substances for which specific indoor air guidelines was recommended.
The working group also recommended guidelines for two additional categories
of risk factors of particular importance to health in indoor environments: biological
agents and indoor combustion (WHO Regional Office for Europe, 2006b).
Biological agents of relevance to health are widely heterogeneous, ranging
from pollen and spores of plants (mainly from outdoors), to bacteria, fungi, algae
and some protozoa emitted outdoors or indoors. They also include a wide variety
of microbes and allergens that spread from person to person. There is strong