# Ensuring Energy Efficiency of Air Quality Monitoring Systems Based on Internet of Things Technology
## 4 Results
Operating modes, such as standby or sleep mode, can significantly reduce energy consumption, which is essential for ensuring the long-term autonomy of IoT systems. Careful selection of sensors and the optimization of their operating modes allow researchers to create efficient and energy-saving air quality monitoring systems. Developing strategies to reduce the energy consumption of sensors is an important aspect of improving the efficiency of IoT air quality monitoring systems. One of the key strategies used is choosing the optimal type of sensor. It is necessary to give preference to those sensors with the lowest power consumption that, at the same time, provide the required level of measurement accuracy needed for a specific task. Optimizing the frequency of measurements is also an effective way to reduce energy consumption. In cases where monitoring conditions allow users to reduce the frequency of data collection, this significantly reduces energy consumption. An important aspect is the use of low-energy data transfer protocols, such as LoRaWAN or Bluetooth LE, which ensure efficient information transmission with minimal energy consumption. The use of energy-efficient microcontrollers also contributes to a significant reduction in energy consumption. Modern microcontrollers with low power consumption allow you to maintain a high level of functionality in IoT devices with lower energy consumption. The application of sleep modes is another important strategy. Putting the sensor to sleep during periods of inactivity can significantly reduce its energy consumption and extend the battery life of the device. The combination of these strategies ensures the creation of energy-efficient solutions for air quality monitoring systems that are more sustainable and durable. There are several popular models of sensors for monitoring indoor air quality available on the Ukrainian market. An overview of some of them, with a focus on their energy efficiency, is presented in Table 2.  
1. 104.ua Air (104.ua, Kyiv, Ukraine) is a smart device equipped with a color screen that informs the system about air quality using color indicators and sound signals. 2. AirHome (Manufacturer/company: \"Free Arduino\", City: Ivano-Frankivsk, Country: Ukraine) is a compact device that measures PM\({}_{2.5}\) and PM\({}_{10}\) particle levels, as well as temperature and humidity. 3. The SaveEcoSensor 3.0 (Manufacturer/company: SaveDnipro. City: Dnipro. Country: Ukraine) is an air quality monitoring station that measures PM\({}_{2.5}\) and PM\({}_{10}\) dust content and is equipped with temperature, humidity, and pressure sensors, as well as a heating module to minimize the impact of weather conditions. This device, when integrated with the SaveEcoBot platform, allows the user to monitor air quality in real time and receive data through a mobile application or website. 4. The Ajax LifeQuality (Manufacturer/Company: Ajax Systems City: Kyiv. Country: Ukraine) features high-precision temperature, humidity, and CO\({}_{2}\) sensors, along with the automation of scenarios for climate control. The LifeQuality sensor works using its own Ajax Jeweller protocol, which provides stable communication with the hub at a distance of up to 1700 m and has minimal power consumption. This allows for reduced electricity consumption compared with Wi-Fi or other wireless standards. 5. Smart Air (Manufacturer/company: GAOTek, New York, NY, USA and Toronto, ON, Canada) is an air quality monitoring device that provides detailed data on indoor air conditions and can integrate with other smart home systems. These devices help monitor indoor air quality, providing a comfortable and safe living and working environment. Analysis of Data Transmission Protocols from the Point of View of Energy Efficiency in Air Quality Monitoring Systems  
Choosing the right data transfer protocol is a critical factor for ensuring the energy efficiency of IoT air quality monitoring systems.