## 7 Results and Discussion
An API key of the thingspeak server loaded in the ESP 8266 Wi-Fi controller enables authentication and interfacing with hardware. As the sensor calibration and firmware development of the hardware is completed, the system is deployed in real-time as shown in Figure 4. Based on the deployment of the system, the sensor directs the sensing analog data to the ATMega 328P controller unit and the analog-to-digital converter converts the analog value into digital. The sensor values such as temperature, humidity level, and air pressure around the environment are processed in the sensor more and transmitted to the gateway through an edge computing-based device through 433 MHz Long-Range module. The different sensor values of the sensor more are logged on the thingspeak server and they are visualized in Figures 14-16. Figure 14a of the thingspeak server dashboard visualizes the PM\({}_{10}\) content of the location at two different time intervals. At 12:30 PM, the PM\({}_{10}\) content recorded on the server is above 100 and when comparing this value in Table 14, the recorded PM\({}_{10}\) is above the optimal range. This indicates that the PM\({}_{10}\) content is high in the air and the health of the air needs to be moderate. Figure 14b of the thingspeak server dashboard visualizes the PM\({}_{2\text{-}5}\) content of the location at two different time intervals. At 12:30 PM, the PM\({}_{2\text{-}5}\) content recorded on the server is equal to 100 and when comparing this value in Table 14, the recorded PM\({}_{2\text{-}5}\) is above the optimal range. This indicates that the PM\({}_{2\text{-}5}\) content is high in the air and the health of the air is poor. Figure 15a of the thingspeak server dashboard visualizes the NO\({}_{2}\) content of the location at two different time intervals. At 12:30 PM, the NO\({}_{2}\) content recorded on the server is above 10 and when comparing this value in Table 14, the recorded NO\({}_{2}\) is in the optimal range. This indicates that the NO\({}_{2}\) content is normal in the air and the health of the air is good. Figure 15b of the thingspeak server dashboard visualizes the O\({}_{3}\) content of the location at two different time intervals. At 12:30 PM, the O\({}_{3}\) content recorded on the server is above 20 and when comparing this value in Table 14, the recorded O\({}_{3}\) is in the optimal range i.e., 0-50. This shows that the O\({}_{3}\) content is normal in the air and the health of the air is good. Figure 16: CO level. Figure 14: (a) PM\({}_{10}\) level (b) PM\({}_{2-5}\) level. Figure 16 of the thingspeak server dashboard visualizes the CO content of the location at two different time intervals. At 12:30 PM, the CO content recorded on the server is equivalent to 1 and when comparing this value in Table 14, the recorded CO is in the optimal range i.e., 0-1.0. This indicates that the CO content is normal in the air and the health of the air is good. Table 15 shows the comparison between previous literature surveys with proposed work. In [39], the performance of the device was verified and validated by measuring air quality by using PM sensor at several indoor and outdoor environments. In [40], a study shown that evaluates the precision, accuracy, and usefulness of a low-cost indoor air quality sensor in a domestic setting for collecting data on indoor pollution. Temperature, relative humidity, total VOC, CO\({}_{2}\) equivalents, and fine PM\({}_{2.5}\) data were collected using five low-cost sensors and compared to data from other scientifically certified monitors. In [41], for industrial and urban regions, an outdoor WSN-based air quality monitoring system was proposed. A trio of gas sensors (O\({}_{3}\), CO, and NO\({}_{2}\)), as well as a ZigBee wireless communication network based on Libelium's [42] gas sensing capable more, make up the sensor node. The ZigBee is used to upload data to the central server. The public can get authorized air pollution information by email, SMS, and a tailored web app. In [43], it was only implemented for indoor air quality.