## 4 Results  
I. The charts of the series collected in Zone 1 (2 and 3) are contained in Figure 2. In Zone 1, 13 points were located around four reservoirs. These facilities were selected for maintenance work to check for seal integrity. The highest concentrations of pollutants were recorded at the extreme edges of the monitored area, predominantly at two points located along a main access road (R20) leading to the reservoirs. The distribution suggests that the pollutants were predominantly dispersed in the direction of this access road, possibly due to existing road traffic, as well as direct exposure from emission sources to the two monitored points, which had a wider opening, facilitating the spread of VOCs without natural or artificial barriers. The potential sources of these pollutants could be direct exposure to emission sources and road traffic. Data analysis indicates that there were no significant accumulations in the points of Zone 1, which are located along the sides or at the intersections of the diagonals of the rectangle circumscribed around the circle formed by the centers of the four monitored reservoirs. In Zone 2, among the 14 measurement points, nine were selected near six reservoirs under maintenance, and 5 points were positioned along the main access road (R4) to the targeted reservoirs. The VOC concentration values exhibited distinct characteristics depending on the location. At the measurement points within the monitored area adjacent to the access road, pollutant concentrations (minimum, maximum, and average) were comparable, indicating a relatively uniform dispersion of VOCs. The result suggests that emissions are evenly distributed near the reservoirs, without significant variations between points on either side of the R4 access road. However, the monitoring points on the access road recorded slightly higher pollutant concentrations. These results can be explained by the accumulation of emissions along the road, which acts as a preferential dispersion pathway, amplifying local VOC concentrations. This observation is supported by the fact that the highest pollutant concentration values were detected at the measurement points located at the ends of the access road. This observation indicates an accumulation of VOC emissions in these areas, where dispersion is less effective, possibly due to physical barriers created by industrial structures (e.g., dikes), various operating systems used, such as petroleum product pumping stations, or determined by the prevailing wind direction. The statistical analysis results may reflect the dynamics of pollutant dispersion, indicating that peripheral points are more exposed to high concentrations due to the accumulation mechanism, local conditions created by air currents, and the site's topography. In Zone 3, the highest pollutant concentrations were found on the access roads (R4 and R9), leading to the monitoring of four other reservoirs undergoing maintenance. These reservoirs are located near the R4 access road in Zone 2 and a second access road (R9) in Zone 3, which are perpendicular to each other. In zone 3, it was observed that the highest pollutant concentrations were recorded at a point near a reservoir that did not have a secondary seal on its cap. The lack of sealing on the reservoir led to uncontrolled VOC emissions, significantly increasing local pollutant concentrations. The seal lack finding underscores the urgent need for effective sealing systems to prevent unchecked pollutant emissions, especially during maintenance periods when the risk of emission leaks is higher. Figure 2: Series recorded at the locations from (**a**) Zone 1, (**b**) Zone 2, and (**c**) Zone 3. Tables S1-S3 from the Supplementary Materials contain the latitudes and longitudes of the observation points and the values of the basic statistics. The series of basic statistics are depicted in Figure S1.