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Several fungi species produce unhealthy volatile metabolites
From the
World
Health Organization in its report WHO Guidelines for
Indoor Air Quality:
Dampness
and Mould, published July 16, 2009
2.3.6 Microbial and other
volatile organic compounds
Several
fungi produce volatile metabolites, which are a mixture of compounds that
can be common to many species, although some also produce compounds
that are genera- or species-specific. Microbial volatile organic compounds
are often similar to common industrial chemicals. To date, more than 200
of these compounds derived from different fungi have been identified
(Wilkins, Larsen, Simkus, 2000, 2003), including various alcohols,
aldehydes, ketones, terpenes, esters,
aromatic compounds, amines and
sulfur-containing compounds. As few of those compounds are specific to
fungi, measuring (microbial) volatile organic compounds is therefore of
limited use in identifying indoor fungal growth. Detection of specific
organic compounds does, however, permit a conclusion of fungal growth
(visible or hidden), even if the results are not quantitative (Moularat et
al., 2008a,b). No larger field studies have been conducted to compare
mouldy and control buildings, and microbial volatile organic compounds
have been measured only rarely in health surveys. Data on airborne
concentrations are therefore scarce.
Some
exposures with adverse health effects associated with damp indoor
environments include emissions of volatile organic compounds from damp and
mouldy building
materials (Claeson, Sandstrom, Sunesson, 2007). Emissions
are a consequence of competition between moisture and some chemicals for
adsorption sites. Volatile organic compounds can be similar to microbial
ones, as both often occur in the same environment. The main difference is
the source of emission, i.e. mould or building materials. Damp concrete
floors have been shown to increase chemical degradation of the plasticizer
in polyvinyl chloride
floor coatings and glues, resulting in emissions of volatile organic
compounds such as 2-ethyl-1-hexanol (Norback et al., 2000; Tuomainen,
Seuri, Sieppi, 2004). Similarly,damp concrete floors may emit ammonia from
the self-levelling flooring compound used in the late 1970s and early
1980s in Europe.
Furthermore, the offgassing of formaldehyde from composite wood products
and the rate of formationof ozone increase with relative air humidity
(Arundel et al., 1986; Godish, Rouch, 1986).
Formaldehyde concentrations may
also be elevated in damp indoor environments because moist air holds more
formaldehyde. The levels of semi-volatile compounds, such as
pentachlorophenol (a
wood preservative) and other pesticides, may also be
elevated in damp indoor environments. No studies have systematically
addressed the link between levels of volatile organic compoundsand
dampness in indoor environments.
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