Due to modern way of life people increasingly spend their time in closed spaces, whether in residential buildings, at work or in transport, and therefore the topic of air quality is becoming more important. There can be a significant difference in indoor air temperature and humidity, the concentration of dust, volatile organic compounds and radiation level in comparison to the environment. That is precisely why monitoring of indicated physical parameters is important in order to establish their effect on human health. In this paper, a DHT22 sensor was used to measure air temperature and humidity, a GeigerMüller counter was used to measure radioactive radiation and a calibrated device Airthings Corentium Pro was used to measure air temperature, humidity and pressure as well as a radon concentration. Since the Airthings Corentium Pro is calibrated to measure radon concentrations, the emphasis of the paper was placed on measuring radioactivity indoors and its effect on human health. By connecting the sensors to Croduino, a Croatian version of an Arduino microcontroller, various ways of recording data were provided such as being recorded on a computer by using the programming language Python, sending to the platform ThingSpeak via the Internet and recording on an SD card. The measurements were performed on the premises of the Faculty of Geotechnical Engineering. By analysing the results of measurements performed by using sensors and by comparing them to the Airthings Corentium Pro device it was determined that the sensors do not deviate significantly.