Download Do building-related complaints reflect expectations?

Proceedings: Indoor Air 2002
DO BUILDING-RELATED COMPLAINTS REFLECT
EXPECTATIONS?
W Bischof1* S Brasche1, B Kruppa2, M Bullinger3 for the ProKlimA Study group
1
Friedrich-Schiller-University Jena, Institute of Occupational, Social and Environmental
Medicine, Department of Indoor Climatology Erfurt, Germany
2
Bundesindustrieverband Heizungs-, Klima-, Sanitärtechnik, Bonn, Germany
3
Department for Medical Psychology, University of Hamburg, Germany
ABSTRACT
Expectations confound the interaction between environment and human perception. Assuming
expectations have an important impact on well-being and behaviour, identifying predictors of
expectations might be a needful task concerning prevention. Thus, data of 4,596 office
workers investigated in phase I of the ProKlimA project have been analysed by multiple
logistic regression to find associations between expectations and potential impact variables.
Women, subjects working in buildings with air conditioning and employees identified as SBS
cases are characterised by consistently higher expectations towards indoor humidity,
temperature, air velocity and ventilation quality. Adjusted odds ratios (OR) for ‘SBS cases’
range between 1.61 and 2.52. The risk of having higher expectations ranges between 1.45 and
1.93 for office workers in spaces with air conditioning compared to naturally ventilated
rooms. With OR from 1.45 to 1.78, women report higher expectations than men. Building
design and facility management should consider related expectations.
INDEX TERMS
Expectation, SBS symptoms, humidity, ventilation, temperature, air velocity.
INTRODUCTION
‘Morphological, spatial, and materialization concepts of office buildings often do not respond
to needs, expectations, perception and response-mechanisms of the human brain ....’
(Trasbsky and Vroon, 1990) is a commonly believed but poorly investigated topic in indoor
air research. Especially, expectations have been claimed to confound the interaction between
environment and human perception.
In the main, two aspects of the indoor environment have been discussed in this context: odour
and thermal comfort. Creuzevault et al. (1990) demand inclusion of social and cultural
analysis of users’ expectations into the development of an indoor air quality prediction model.
Therefore, the authors attempt to provide users with better answers regarding control of heat
and odour in respect to indoor air quality. Dalton et al. (1996), investigating responses to
volatile chemicals, found ‘strong evidence that both the perceived odor and cognitive
expectations about a chemical can significantly affect how individuals respond to it’. These
findings are consistent with other studies (Knasko, 1992; Schoen, 1997). Concerning thermal
comfort aspects Auliciems (1973) concludes that discrepancies between predicted and
observed parameters must have resulted from some more subtle and less easily identifiable
process of behavioural or physiological adaptation. Cultural expectations (Cena and
Sliwowski, 1995) and context-specific expectations (Olesen et al., 2001) might influence the
*
Contact author email: [email protected]
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Proceedings: Indoor Air 2002
satisfaction with an indoor climate. Thus, satisfaction ‘results from matching thermal
conditions in a given context and one’s thermal expectations of what the indoor climate
should be like in the same context’ (de Dear and Brager, 2001).
Assuming that expectations are an important impact on well-being and behaviour, identifying
predictors of expectations might be a needful task to prevent adverse health effects.
METHODS
Between 1995 and 1998 14 German office buildings were surveyed by ProKlimA, a
multidisciplinary project group [Bischof 1999]. In Phase I of the project an initial
questionnaire was applied to all employees of these buildings. Amongst others, the selfadministered questionnaire included a sensory perception module consisting of 9 to 11 items
pertaining to 6 different sub-scales and questions related to job satisfaction, allergies, acute
illness and to psycho-social and demographic factors [Bullinger 1993]. In addition, the
subjects were asked to express their expectations concerning selected parameters of the indoor
environment such as lighting, temperature, humidity, ventilation quality, sound level, air
velocity and perceived air quality on a 5-point-scale (not, slightly, quite, very and extremely
important). Voting ‘extremely important’ has been defined as ‘highly expectant’.
Demographic and psycho-social parameters known to be associated with building-related
symptoms (Brasche 1999), the type of ventilation (air conditioning vs. natural ventilation) and
the expression of symptoms itself (defined as at least 2 subscales of the sensory perception
module having at least 3 items ”minor annoying” or more = ‘SBS case’) have been set as
explanatory factors. Associations between expectations and explanatory factors are presented
as odds ratios. Statistical software SAS, Rel. 8.0 was used for the calculation including linear
logistic regression models (OR).
RESULTS
In total 4,596 office workers took part on phase I of the ProKlimA investigation in 14 office
buildings. Table 1 presents the distribution concerning explanatory variables of the
investigated sample.
Table 1. Sample characteristic concerning potential explanatory variables
VARIABLE
Female sex
≤ 30 years
Low educational level
Self reported acute illness
Self reported allergy
Cold season
Low job satisfaction
‘SBS case’
Air conditioning
NO
YES
n
%
N
%
2001
3340
44.3
74.1
2512
1170
55.7
25.9
2193
3647
3127
3249
3292
2826
1882
50.0
83.3
68.1
70.8
71.7
63.0
41.0
2194
730
1462
1340
1297
1656
2707
50.0
16.7
31.9
29.2
28.3
37.0
59.0
Results of the multiple logistic regression analysis are shown in Table 2.
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Proceedings: Indoor Air 2002
Table 2. Adjusted odds ratios (OR) and 95% confidence intervals (CI) for expectations
towards humidity, temperature, air velocity and ventilation comparing demographic, psychosocial factors, building related symptoms and type of ventilation.
expectations towards indoor ⇒
sample size
prevalence, %
female vs. male
≤ 30 years vs. older
low educational level
self reported acute illness
self reported allergy
cold season
low job satisfaction
‘SBS case’
Air conditioning (AC)
humidity
temperature
air velocity
ventilation
4,067
12.5
4,074
16.7
4,048
7.8
4,074
23.1
OR Ci_l\Ci_u
OR Ci_l\Ci_u
OR Ci_l\Ci_u
OR Ci_l\Ci_u
1.60 1.27\1.99
1.16 0.94\1.44
1.78 1.46\2.16
1.66 1.38\2.00
1.45 1.10\1.90
1.03 0.79\1.34
1.62 1.37\1.93
1.65 1.40\1.95
1.06 0.86\1.30
0.97 0.75\1.24
1.08 0.88\1.32
1.04 0.78\1.37
1.23 1.00\1.52
2.51 2.04\3.08
1.72 1.33\2.22
1.06 0.88\1.27
0.89 0.71\1.12
1.03 0.86\1.24
1.06 0.84\1.35
1.05 0.87\1.28
1.61 1.35\1.93
1.65 1.32\2.05
1.44 1.11\1.86
1.13 0.84\1.51
0.95 0.74\1.22
1.25 0.88\1.76
1.19 0.92\1.53
2.52 1.95\3.24
1.93 1.39\2.66
0.95 0.81\1.12
0.91 0.74\1.11
1.12 0.96\1.32
0.92 0.75\1.14
1.12 1.00\1.41
1.87 1.59\2.19
1.45 1.20\1.76
Expectations toward ventilation are characterized by the highest prevalence – almost a quarter
of all subjects investigated judge ventilation quality as an extremely important issue.
Prevalence concerning air velocity are the lowest with 7.8 %.
Statistically significant associations (p<0.05) concerning all 4 types of expectations were
found for sex, SBS symptoms and type of ventilation. Consistently higher expectations were
reported from women, subjects identified as SBS cases and those working in buildings/indoor
spaces with air conditioning. Subjects below 31 years of age report higher expectation
towards temperature and ventilation. Low job satisfaction is associated with significantly
higher expectations towards indoor humidity and ventilation. Subjects characterized by a low
educational level report higher expectation towards air velocity. No associations were found
between expectation and disposition (acute illness, allergy) or season.
Significant intercorrelations between all types of expectations exist at a low to medium level.
Pearson correlation coefficients range from 0.352 to 0.442 (p<0.0001).
DISCUSSION
Expectations toward the indoor environment are influenced by multiple factors. Thermal
comfort – the ‘oldest’ field of systematic research related to the indoor environment – has
already included alternatives to explain artefacts of the conventional comfort theory. Thus, the
adaptive model understands that ‘building occupants are not simply passive recipients of their
building’s internal thermal environment, like climate chamber experimental subjects, but
rather, they play an active role in creating their own thermal preferences’ (de Dear and Brager,
2001). Such preferences are understood to be influenced by past thermal experiences and
current thermal expectations. Differences between predicted and observed comfort parameters
have been noticed mainly in naturally ventilated buildings, where comfort temperatures show
a much wider range as predicted by the PMV model (Olesen et al., 2001). Similar tendencies
have been noticed for mean indoor air velocities (de Dear and Brager, 2001). In our sample,
adjusted odds ratios show too a significant risk of higher expectations toward temperature and
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Proceedings: Indoor Air 2002
air velocity from subjects who work in buildings with air conditioning. Above that, working
in AC buildings is associated with generally higher expectations concerning indoor air, such
as ventilation quality and humidity.
Expectations toward lighting, sound level, and perceived air quality (data not shown) are not
characterised by higher risk for AC buildings but are associated with SBS symptoms. Thus,
light, sound and smell seems to be a matter of general concern and not specifically related to
air conditioned spaces.
With the inclusion of the information that those subjects complaining about SBS symptoms
report consistently higher expectations into SBS models their ‘background noise’ might be
reduced and such, identifying additional impact factors might be possible. On the other hand,
changes in the level of expectations might be a consequence of past sensory and/or psychosocial experiences.
CONCLUSION
Subjects’ expectations have a remarkable impact on the prevalence of building-related
symptoms. Women, employees working in office buildings with air conditioning and subjects
reporting SBS symptoms are characterised by consistently higher expectations (significant OR
rage from 1.45 to 2.52) towards indoor humidity, temperature, air velocity and ventilation
quality. Building design and facility management should consider related expectations of
occupants.
ACKNOWLEDGEMENT
The ProKlimA-project was supported by a grant of the German Ministerium für Bildung,
Wissenschaft, Forschung und Technologie (BMBF).
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