## 4 Results
The following variation intervals of the values are determined in the study zones (1, 2, and 3, respectively):  
* For the minimum (mg/m\({}^{3}\)): [1.2, 12.69], [0.62, 15.75], and [3.96, 11.15];
* For maximum (mg/m\({}^{3}\)): [25.98, 164.53], [12.98, 102.47], and [21.24, 147.42];
* For the average (mg/m\({}^{3}\)): [14.95, 52.29], [3.21, 50.56], and [12.93, 45.33];
* For the standard deviation (mg/m\({}^{3}\)): [5.48, 43.39], [1.85, 24.82], and [4.16, 33.37];
* For the skewness coefficient: [\(-0.37\), 1.48], [\(-1.33\), 2.53], and [0.03, 2.92];
* For the kurtosis: [\(-1.86\), 1.51], [\(-1.07\), 7.41], and [\(-1.25\), 5.85]. The limits of the intervals to which the standard deviations belong vary significantly. The same is true for the skewness and kurtosis of the series recorded in different zones. We notice right- and left-skewed series in Zone 1 and mostly (almost) symmetrical and right-skewed series in the other zones. Maxima varied in large limits, with the highest amplitude in Zone 3 and the lowest in Zone 2. The maps of the spatial distributions of minimum, maximum, and average concentrations in Zone 1 (2 and 3) are presented in Figure 3 (Figures S2 and S3). The maps were drawn considering the results from all measurement campaigns, averaging them, as explained in Methodology. Given the relatively low height at which the measurement was done and the walls around the tank area, the influence of wind is not significant. Therefore, the maps provide information about the extent of pollution. Of course, more experiments must be done to adjust them. Figure 3: Maps reflecting the spatial distribution of the (**a**) minimum, (**b**) average, and (**c**) maximum concentrations in Zone 1. II. The boxplots of all series are shown in Figure 4. They are built using the quartiles. The bottom (top) horizontal line corresponds to the first (third) quartile, \(Q_{1}\) (\(Q_{3}\)), and the horizontal line inside the box is the median (\(Q_{2}\)). The whiskers represent the ranges for the data series' top and bottom 25% values, respectively, without considering the outliers. Figure 5 (left) contains the correlogram and the PACF chart of the Z1M10 series. They show a first-order autocorrelation and partial autocorrelation of the Z1M10 series. The examination of the correlograms of all series indicates that 7 series from Zones 1 and 2 and 5 from Zone 3 present a first-order autocorrelation. PACFs reveal significant partial autocorrelations (at a significance level of 95%) of the first order for 7 series from Zone 1 and 5 series from Zones 2 and 3. The normality tests rejected the null hypothesis for 7 series in Zone 1, 8 in Zone 2, and 9 in Zone 3. Figure 6 displays the QQ plot of the Z1M14 series. The samples' quartiles (represented by dots) do not align with the theoretical (Gaussian) ones (represented by  
Figure 4: Boxplot of the series from (**a**) Zone 1, (**b**) Zone 2, (**c**) Zone 3. The stars represent the outliers. Figure 5: (a) ACF and (**b**) PACF of the Z1M10 series. The blue bars represent the ACF values at different lags. The dashed lines are the limits of the 95% confidence intervals. the line), showing that the data series is not normally distributed. The homoskedasticity hypothesis was rejected for one, six, and four series from Zones 1, 2, and 3, respectively. Table 2 summarizes the features from the above statistical analysis (performed according to point II from Methodology). It also contains the autocorrelation and partial autocorrelation orders and the number of outliers in the series recorded at each point. The rejection of the normality (homoskedasticity, respectively) hypothesis is marked by 0. These features will be utilized in the clustering stage. III. The correlation matrix of the series in Zone 1 (2 and 3) presented in Figure 7 (Figure S4) indicates very few significant correlations. The distance correlation \(t\)-test of independence confirmed the results.