## 2 Methods
### \(\sum IAQ\) Model Scheme Morphology
First, the model was cut by a cross-connected vertical connection regarding the inputs of submodels--the calculation of the sum of the masses of all pollutants \(\sum c_{j}\) in the ventilated space, using the values for the inputs of all submodels of IAQ concentration values of contaminants. The sum of the concentrations of all air pollutants expressed as mass units of pollution per m\({}^{3}\) of volume (which can be read after multiplication by \(V\) (m\({}^{3}\)) as the mass to be displaced by ventilation), is the basis for calculating the \"air change rate per hour\" (ACH), the minimum air exchange rate needed to reduce the observed mass level of air pollution in a ventilated room (see Reference [40]). The second connection concerns the submodel outputs--the conversion of excess concentration to a dimensionless value, which allows to for the weighting scheme of the \(\Sigma\)IAQ\({}_{\text{index}}\) combined model and the weights of individual IAQ submodels to be determined. Additional assumptions were as follows:  
1. The sum \(\sum\Delta c_{1,\,\ldots\,\,7}\), which admittedly constitutes an excess mass increase of the sum of pollutants described by the submodels, was treated only as a \"virtual energy load of the building\" for ventilation conducted for the elimination of pollutants, and therefore, when adjusting the weights, the possibility of dividing the excess concentration by the sum of concentrations should be considered. 2. The percentage of persons dissatisfied _PD(IAQ\({}_{\text{\emph{component}}}\))_ determined experimentally in sensory studies using panelists' sense of air quality during their exposure to an internal environment deteriorated by a given contamination component (_PD = f_ (c_j)), was derived from the literature or direct experiments. Values of weights \(W_{1,\,\ldots\,j}\) in sets of three, five or more components of the three \(\sum\)IAQ\({}_{\text{index}}\) models (see Equations (12)-(14), were adjusted to a value of unity by dividing \(\Delta c_{1,\,\ldots\,j}\) of each component by the sum of excess concentrations \(\sum\Delta c_{1,\,\ldots\,j}\) in \(\mu\)/m\({}^{3}\). We proposed the use of \(c_{\text{{ref}}}\) values, apart from the values of \(c_{\text{{LCI}}}\)[18], \(c_{\text{{ELV}}}\), and the threshold values \(c_{\text{th}}\) for odorous compounds, were as follows. 1. For IAQ(CO\({}_{2}\)) and IAQ(HCHO), the \(c_{\text{{ELV}}}\) concentrations were derived from EN 16798-1:2019 [10];
2. For IAQ(TVOC) and IAQ(VOC\({}_{\text{odorous}}\)), the threshold concentrations, \(c_{\text{th}}\), for identified odorous compounds or mixtures are from Reference [44];
3. For the IAQ(h), the water-vapor concentration H (g\({}_{\text{w}}\)/m\({}^{3}\)), recalculated from the moisture content x (g\({}_{\text{w}}\)/kg\({}_{\text{dry air}}\)) using the gas constant for the water vapor and the actual temperature, the value of \(h\) up to the critical value for \"high enthalpy of humid air\" was evaluated using the formula: \[h=1.006t_{a}+\text{x}\cdot(2501+1.805t_{a})\] (15) where \(h\) is the specific enthalpy of humid air (kJ/kg), which must be \(>\)55 kJ/kg. The EN 16798-1:2019 standard [10] recommends a limit for the dehumidification of air of 12g\({}_{\text{w}}\)/kg\({}_{\text{dry air}}\) (this value must be converted to a \(c\) value in g\({}_{\text{w}}\)/m\({}^{3}\)). 4. For IAQ(VOC\({}_{\text{non-odorous}}\)), the \(c_{\text{{ELV}}}\) value in cases where no established LCI values were derived from the EN 16798-1:2019 standard. 5. For IAQ(PM\({}_{2.5}\), PM\({}_{10}\)), the \(c_{\text{{ELV}}}\) values were derived from the WHO [7] or other organizations (Tables 1 and 2). The proposed reference values of pollutants forming the sub-indices of the IAQ model are given in Table 2. With reference to the concentration values of \(c_{\text{{LCI}}}\), it should be noted that according to References [18], this value is typically acquired by dividing occupational exposure limits by a safety factor (100 or 1000).