# System for Indoor Comfort and Health Monitoring Tested in Office Building Environment
## 4 Results and Discussion  
The meteorological and comfort parameters (temperature, relative humidity, CO\({}_{2}\)) were simultaneously monitored in all three spaces, while the health parameters (TVOCs, HCHO, PM and \({}^{222}\)Rn) were monitored only in Office 1. The parameter variation during the preliminary testing time frame led to the plot of the following diagrams. Figure 6 shows the variation in meteorological parameters over the testing period inside Office 1. Considering that the monitoring period was characterized by high outdoor temperatures (34-39 \({}^{\circ}\)C) and also the fact that AC systems were not used, the registered values constantly exceeded (indicated with a green line in Figure 6) the satisfying comfort values from Table 4. The data analysis showed that the average comfort value of 26 \({}^{\circ}\)C was exceeded for 91.66% of the working time. However, the relative humidity values fell within the values recommended for the summertime, below 60% (indicated with a blue line in Figure 6). The results of the temperature and the relative humidity for the other two monitored spaces are shown in Figures 7 and 8. Office 2 and PV-testing laboratory data analysis also showed that the temperature threshold value (indicated by green lines in Figures 7 and 8) was constantly exceeded: 99% of the working time in Office 2 and 83.33% of the working time in the PV-testing laboratory, respectively. Reduced temperature values of around 23 \({}^{\circ}\)C can be noticed in Figure 7 on 21 July 2023, when the AC was running while performing tests of photovoltaic modules, which required specific thermal conditions. As in the case of Office 1, the relative humidity values in these monitored spaces were in accordance with the values recommended for summertime comfort. Figure 6: Variation in meteorological parameters over the preliminary testing period in Office 1 measured using the IoT system. Figure 9 shows the variation in CO\({}_{2}\) over the testing period in Office 1. As expected, the highest CO\({}_{2}\) values, up to 1500 ppm, were registered in the late afternoon of the working days when the room became unventilated, in accordance with Table 1. This is due to the fact that the occupants kept the windows and door closed. During night-time, the values dropped to 500-600 ppm, which is appropriate for ventilated spaces. The weekend period can be easily identified since the values had almost no variations, oscillating around 500-550 ppm. The recorded data suggest the need for a new ventilation system installation. Based on the CO\({}_{2}\) measurement, when reaching certain thresholds, the system should automatically start ventilation until the comfort parameters are achieved. This is intended to be achieved considering that exposure to high CO\({}_{2}\) values can lead to health issues like  
Figure 8: Variation in meteorological parameters over the preliminary testing period in the PV-testing laboratory measured using Netatmo weather station. Figure 7: Variation in meteorological parameters over the preliminary testing period in Office 2 measured using Netatmo weather station. inflammation, a reduction in cognitive abilities, bone demineralization, kidney calcification or oxidative stress [45]. The CO\({}_{2}\) values in the other two monitored spaces are shown in Figures 10 and 11. Office 2 and PV-testing laboratory data analysis showed that the occupants' comfort was ensured most of the time, with a single exception when a peak of 1140 ppm was registered. This happened in Office 2 due to an increase in the occupancy level for a work meeting. Figure 12 shows the variation in TVOCs over the testing period inside Office 1 as well. It should be mentioned that this Office space is located right next to the CATL, which usually develops tests and experiments with volatile substances. Also, according to the U.S. Environmental Protection Agency [46], the guideline values must fall below 120 ppb.