Environmental Engineering Reference
In-Depth Information
continuing during winter, and resolving in spring. It is thought to result
from body biochemical changes associated with decreases in solar intensity
and photoperiod. Building occupants with high SAD scores have signifi-
cantly higher symptom prevalence rates, which decrease as the winter season
ends and spring begins.
4.
Significance of psychosocial factors and SBS-type symptoms
The most scientifically plausible explanation of the observed relationship
between psychosocial factors and SBS-type symptoms (other than potential
effects of SAD) is the effect of the former on symptom reporting rates. It can
be anticipated that individuals experiencing work-related stress are more
likely to report symptoms (when they occur), and those experiencing little
or no stress are less likely to report symptoms. Similarly, individuals report-
ing high job satisfaction may be less likely to report symptoms even when
present. The effect of psychosocial factors may be indirect (affecting report-
ing rates) rather than direct, as is often supposed.
C. Tobacco smoking
Studies that have evaluated passive smoking as a risk factor for SBS-type
symptoms have consistently shown a relationship between office workers'
perception of exposure to environmental tobacco smoke (ETS) and increased
symptom prevalence. Several studies have shown weaker relationships
between objective measurements and symptom prevalence. These studies
indicate that exposure to ETS may increase the rate of SBS-type symptom
reporting. Danish studies assessing satisfaction or dissatisfaction with air
quality using trained panels indicate that about 25% of reported dissatisfac-
tion with perceived air quality in office buildings is due to ETS.
Exposure to ETS may have an indirect effect. Because of subjective
annoyance with ETS, it is probable that those exposed to it will report
increased SBS-type symptoms.
Most studies evaluating the relationship between ETS and SBS-type
symptoms have been conducted in northern Europe, where tobacco smoking
rates are high and common in nonresidential buildings. In North America,
smoking restrictions are in place in restaurants and a large majority of non-
residential, nonindustrial buildings. As a consequence, ETS is unlikely to be
a risk factor for building-related illness symptoms in most North American
nonresidential buildings.
D. Environmental factors
Environmental conditions in building spaces at any given time are due to a
number of physical variables. These include air temperature, relative humid-
ity (R.H.), air movement, ventilation, lighting, noise, vibration, and electrical
and magnetic phenomena. Many of these environmental factors have been