# A Systematic Literature Review of LoRaWAN: Sensors and Applications
## 3 Results
### Applications of LoRaWAN
#### 3.1.2 Environmental Monitoring  
Environmental monitoring is the most frequent application of LoRaWAN among the previous works analyzed in this paper. Among these applications, it can be seen that the measurement of ultraviolet (UV) rays, the monitoring of air quality, and the monitoring of water stand out. In [14], a monitoring system was created to assist in the prevention of diseases caused by solar radiation through Twitter alerts using LoRaWAN technology and ThingSpeak software. In [18], the UV-radiation measurement procedure was also performed using an ESP32 controller. In [19], commercial sensors were used to implement the measurement of ultraviolet radiation with an optimization of energy that allows them to work up to 14 days; communication was also optimized for distances greater than 0.7 km. In [24], the design of a device based on UV optical sensors that allows determining the existing radiation index \begin{table}
\begin{tabular}{l l} \hline \hline
**Area** & **References** \\ \hline Agriculture & [9; 10; 11; 12; 13] \\ \hline Environmental Monitoring & [2; 4; 10; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26] \\ \hline Mobility & [27; 28; 29; 30; 31] \\ \hline Health & [6; 17; 32; 33; 34] \\ \hline Other areas & [1; 8; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51; 52; 53; 54; 55; 56; 57; 58; 59; 60; 61; 62; 63; 64; 65] \\ \hline \hline \end{tabular}
\end{table} 
Table 6: References organized by their application areas. was presented; ultraviolet radiation index (UVI) levels were displayed through a graphical user interface in real time, which also allowed generating a report in a.csv file. The study was carried out in the central patio of two educational units. In another work, the authors created an air-quality measurement system taking into account parameters such as CO\({}_{2}\), No\({}_{2}\), PM (particle matter) levels, temperature, and humidity [15]. This was achieved using sensors and a communications module. The used sensors were inexpensive and required extensive calibration given the interactions of temperature and humidity. In [20], low-cost air-quality sensors were used, such as those for measuring the level of particles, SO\({}_{2}\), NO\({}_{2}\), CO, O\({}_{3}\), and CO\({}_{2}\); in this system, the sensors send the data directly to an application through the LoRaWAN network, and the collected data are presented through an interface that allows to see the evolution of the measured parameters through graphs with a granularity of day, week, or month. The results of the work confirmed that LoRaWAN is appropriate for this type of monitoring solution. On the other hand, in [22], an IoT system was proposed for monitoring environmental parameters such as temperature, air pressure, humidity, noise, and air quality; the collected data are sent to a cloud server that saves and displays the measurement data. On the other hand, in [25], two stages of an air-quality monitoring system were established to facilitate the environmental changes in the regional air condition and early warning system. First, the air-quality sensors from Arduino and LoRa were integrated; the sensor nodes were then deployed on a university campus. Another work is the one presented in [2]; in this work, the authors proposed a monitoring system for moisture in the wood of buildings with cultural significance. The sensing solution was composed of a LoRaWAN communication device and a cloud application that allows remote visualization and control of the building's nodes. The results showed that the proposed system can be applied inside buildings, despite obstacles such as thick walls and complex architectural structures. In [23], an environmental monitoring solution with parameters such as temperature, humidity, barometric pressure, and ambient light was proposed. The nodes were attached to a vehicle that shows the behavior in motion. The gateway was connected to the servers which deliver the gathered data to the end users.