## 3 Results  
### Probability of Abnormal IA Exposure and Employees' Experience  
All building floors or sections (total 111) were investigated and we were able to assess the probability of abnormal IA exposure on or in 95 building floors or sections. In the case of forty building floors or sections, the assessment of the probability of abnormal IA exposure and IA questionnaire could both be conducted in the same areas (the IA questionnaire group was located in the area that was assessed as belonging to an abnormal IA exposure category). The probability of abnormal IA exposure was assessed as _unlikely_ for 5% (n = 2), _possible_ for 40% (n = 16), _likely_ for 45% (n = 18), and _very likely_ for 10% (n = 4) of the selected forty floors or sections of the buildings. In the _likely_ and _very likely_ categories, these floors or sections had wide moisture and mould damage in their structures together with air leaks from damaged materials to the IA and often had a detected MMVF source in the ventilation system as well as ventilation deficiencies (Table 2 and criteria in Table 1). These categories also had other impurity sources (Table 1), but moisture and mould damage in the building structures were dominant. The higher (more abnormal) the assessed category of probability of abnormal IA exposure, the more insufficient the ventilation was, the more often the lifespan of the ventilation system was exceeded and the more often MMVF sources were detected in the ventilation system from the categories likely and very likely (and not from unlikely category) (Table 2). The perceived weekly work environment-related symptoms among the employees exceeded the corresponding number of weekly work environment-related symptoms in FIGH's reference data [28; 29] (Figure 2). Even in premises in which the building research showed no source of contamination, some employees perceived weekly symptoms more than those in FIGH's reference data [28; 29] (Figure 3). An analysis of the differences between the probability of abnormal IA exposure categories (_unlikely_, _possible_, _likely_, _very likely_) and the employees' weekly perceived work environment-related symptoms (headaches, concentration difficulties, irritation of the eyes and nose, irritation of the skin on the face and hands, hoarse throat, coughing, coughing at night, shortness of breath, wheezing, fever or chills, joint pain, and muscular pain revealed no statistically significant differences (Table 3). \begin{table}
\begin{tabular}{c c c c c} \hline
**Assessed Probability of** & **Lifespan of** & & & **MMVF (Man-Made** & **Moisture Problem** \\
**Abnormal IA Exposure** & **Ventilation** & **Insufficient** & **Vitreous Fibres) Source** & **in Ventilation** \\
**on/in Building Floors or** & **System Had Been** & **Ventilation** & **in Ventilation System** & **System** \\
**Sections** & **Exceeded** & **n (\%)** & **n (\%)** & **n (\%)** \\
**(n = 95)** & **n (\%)** & & & \\ \hline Unlikely (n = 7) & 7 (100) & 3 (43) & 3 (43) & 0 (0) \\ Possible (n = 39) & 23 (59) & 22 (56) & 12 (31) & 6 (15) \\ Likely (n = 37) & 26 (70) & 24 (65) & 26 (70) & 15 (41) \\ Very likely (n = 12) & 10 (83) & 9 (75) & 9 (75) & 1 (8) \\ \hline \end{tabular}
\end{table} 
Table 2: Ventilation survey findings are included in all the sections or floors in which probability of abnormal IA exposure was assessed (95 floors or sections). (All building floors or sections (111) were investigated and we were able to assess the probability of abnormal IA exposure on or in 95 building floors or sections.). Figure 2: In the buildings assessed for probability of abnormal IA exposure, weekly work environment-related symptoms (n = 1558) were perceived more often than in the Finnish Institute of Occupational Health’s (FIGH) comparable reference data [28].