|dc.description.abstract||In 2004, symptoms, perceptions and indoor exposures were studied among 173
(86%) of the employees in four University buildings of which two were claimed to
have dampness problems (problem buildings), two other buildings served as controls.
In addition, physiological signs from eyes, airways and blood were examined. The
main objective was to study symptoms and physiological signs in relation to the
The buildings were inspected and characterised, including noise and lighting
assessments. Indoor climate measurements of air temperature (T-air), relative
humidity (RH%), carbon dioxide (CO2), air velocity, and particulate matter, assessed
gravimetric as particles with less than 10 μm aerodynamic diameter (PM10), were
performed in a number of representative rooms that were categorised according to
location, size and function. In total, 56 logging points were covered. The logging
periods were mostly set to two days (9 am to 4 pm) and one night (4 pm to 9 am) in
each room. Measurements were collected every fifth minute through the monitoring
period for the thermal data, CO2, air velocity and RH%. Outdoor meteorological data
were also collected. The results were modelled according to building and office size
in order to assign data for the work site of all participants. Microbiological
assessments included viable microbiological sampling in air aiming to compare
microbial flora composition between outdoor air, air intakes and indoor air. Air
samples were collected from outdoors near the air inlets, inside the ventilation
aggregates, between the filter and the fan, in technical rooms and in user areas
including offices. A total of 191 air samples were collected.
A questionnaire with standardised questions about symptoms and perception of
indoor climate, demographic and life-style factors, home environment and job
demands, control and social support at work were answered by the participants. A
symptom score (SC) was constructed from the number of weekly symptoms. Job
demands and control were combined to the factor “strain”. Multiple linear and
logistic regressions were applied.
A medical investigation was performed at the workplace in March 2004, after the
influenza season and before the pollen season. Tear film break-up time was measured
by ocular microscopy (NIBUT) and by recording the time the individual could keep
their eyes open without blinking (SBUT). Nasal patency was measured by acoustic
rhinometry. Nasal lavage fluid analysis (NAL) included eosinophilic cationic protein
(ECP); myeloperoxidase (MPO), lysozyme and albumin. Total serum IgE and
specific IgE (Phadiatop®) were analysed.
The microbial airborne flora was normal in all buildings and other environmental
exposures were within prevailing requirements and recommended standards.
Comparing the buildings, no differences were found in psychosocial environment. Workers in the problem buildings had higher prevalence of one dermal and five
general symptoms, but no increase of ocular, nasal or other respiratory symptoms,
specific IgE (Phadiatop), total IgE or any physiological signs.
In general, both NIBUT and SBUT were shorter at lower night temperature. Adjusted
day NIBUT and SBUT increased at higher night air temperatures with B; 95% CI:
0.6; 0.04-1.2 and 1.3; -0.02-2.5, respectively. Low air temperature at 6 a.m. was
associated with decreased tear film stability during work hours. This association was
weaker for air temperature at 8 a.m. and no associations were found for air
temperature at 10 a.m. Higher relative humidity at mean day air temperature < 22.1oC
was associated with increase of adjusted NIBUT and SBUT; B; 95% CI: 0.16; 0.03-
0.29 and 0.37; -0.01-0.75, respectively. Air velocity below prevailing winter
recommendations and lower relative humidity in the range of 15-30% were
associated with perceiving dry air and too low temperature.
15% of the participants had a damp dwelling, and 20% had a cat or dog. Home
building dampness was associated with increased NAL-lysozyme (p=0.02) and an
increase of airway infections (OR=3.14: p=0.04). Pet keeping was associated with
more difficulties to concentrate, feeling heavy-headed and tiredness but less airway
Women reported more often health symptoms than men and also more complaints on
physical but not psychosocial factors at work. Men’s symptoms and complaints were
more specifically associated to air velocity and humidity. For both genders,
symptoms were related to both strain (P=0.02) and perceived physical environment
(P=0.01). Lower relative humidity in the range of 15–35% was associated with
perception of too low temperature and dry air.
Perceiving “dry air”, having ocular symptoms and lower BUT were strongly
associated in office environment employees. To have experienced “ever asthma” and
“ever hay fever” were predictors for symptoms and perceived air quality respectively.
Markers of atopy in terms of Phadiatop, Total IgE, familiar allergy and “ever
eczema” were not associated to symptoms or perceived environments. Gender was
associated to environmental perceptions, BUT and nasal patency. Age was associated
to nasal patency. Recent airway infections were predictors for nasal lavage markers.
In conclusion, workers in the problem buildings had more general and dermal
symptoms, but not more objective signs than the others. However, thermal climate
and ventilation in university buildings, may affect both symptoms and physiological
signs. Both gender, psychosocial and physical environment factors were related to
symptoms and perceived indoor climate. Reduced night time temperature might
create impaired indoor environment. A combined use of questionnaires of symptoms,
perceived air environmental complaints, measurements of tear film break up time,
nasal patency and NAL-markers can be a useful method to study human reactions to
the indoor environment. A holistic perspective is needed.||en