Toxicity Issues: Indoor Air Quality - Nearly Zero Energy Building Refurbishment - page 320

pollutants such as VOCs, SVOCs and PAHs. Studies focused exclusively on
biologic pollutants were not included in Table 1 , but some epidemiological studies
investigating

associations between dampness and mould and asthma were

reviewed by Sahakian et al. ( 2008 ).

1.3 Multidisciplinary Approach of IAQ Assessment

IAQ problems depend on a number of factors such as the existing indoor pollu-
tants, their concentration, and their adverse effects on human health. Therefore, the
investigation of IAQ requires multidisciplinary groups of experts in heating,
ventilating, and air conditioning (HVAC), IAQ control, epidemiology, toxicology
and exposure assessment among others. The number of indoor pollutants and their
concentration depend on several factors, such as indoor sources, features of the
building and the accumulation processes of pollutants (de Blas et al. 2012 ; Uhde
and Salthammer 2007 ). The type and number of indoor sources determine both the
pollutants emitted and their emission rates; chemical transformation and indoor
accumulation will depend on each individual species and, hence, on indoor
chemistry (Weschler 2011 ).
When an existing building undergoes a major renovation, it should satisfy the
minimum energy performance requirements in order to fulfil nearly zero energy
refurbishment. Besides, IAQ should be maintained to ensure the welfare of the
occupants; it should be improved whenever possible. There is a general trend of
using low-polluting materials, but those materials should be certified and labelled.
Ventilation rates should be adjusted to certify acceptable IAQ levels, but it is not
beneficial to increase them at any rate, since they would lead to energy loss.
Considering all those factors affecting IAQ assessment, the sections of this topic
chapter are organised as follows:

• Section 2 describes the main indoor pollutants individually, selected for their
hazardousness with respect to health effects. Major indoor sources, indoor and
outdoor concentrations, and health effects are described.
• Section 3 describes ventilation and infiltration processes in buildings, which
determine the effectiveness of removing pollutants from indoor air and the
intrusion of outdoor pollutants.
• Section 4 discusses the control measures to be applied for the improvement of
IAQ using a multidisciplinary approach.