Civil Engineering Reference
In-Depth Information
Wyon
2007
) as in epidemiological studies (Haverinen-Shaughnessy et al.
2011
;
Lee et al.
2012b
). Particle filtration in the classroom did not have a similar effect
(Wargocki et al.
2008
).
Similar effects were observed for office workers (Seppänen et al.
2006
), both for
simple, repetitive tasks (Wargocki et al.
2002a
) and for more complex strategic
decision making (Satish et al.
2012
). Although the effect is rather small, a few % of
productivity gain, the economic value of that increase in productivity is much
higher than the cost of increased ventilation (Fisk et al.
2012
; Wargocki and
Djukanovic
2005
)
1.1.3 Comfort Effects
Ventilation flow rates, as a proxy for pollutant concentrations, have been shown to
improve the perceived quality of the indoor air (Fanger
1988
; Frontczak et al.
2012
) as well a number of acute physiological complaints such a dry eyes, blinking
rate, dry throat, head ache usually grouped under the term 'sick building syn-
drome' (Seppanen and Fisk
2004
). The correlation fades at flow rates higher than
25 l/s/person.
Some of these symptoms were attributed to specific pollutant types, such as
human metabolites (Claeson et al.
2009
) or volatile organic compound (VOC)
emissions from common building materials (Johnsen et al.
1991
; Gminski et al.
2011
).
Occupants have reported discomfort at excessive humidity levels, especially in
hot conditions (Toftum et al.
1998a
; Toftum et al.
1998b
), and there are some early
indications that high pollution loads have an impact on the quality of sleep and
dreaming (Schredl et al.
2009
; Laverge et al.
2012
).
Other parameters, such as temperature, acoustics and air speed, definitely
influence occupant comfort, but are not directly related to the reduction in pol-
lutant levels, which is considered the primary goal of ventilation in this chapter,
and are therefore not discussed further.
1.2 Sources
Within the indoor built environment, the main sources of the pollutants associated
with adverse effects can be grouped in three categories: the building itself, and
more specifically the building materials used in it, the activities of the building
occupants inside the building in general or in specific locations of the building and
pollutants coming from the outside environment penetrating into the indoor
environment. In the following paragraphs, these categories are each discussed
more in detail.
