<p>One of the crucial goals in the sustainability of smart cities, which play a significant role in the health and quality of life of citizens, is to increase the quality of the urban environment, and urban heat islands have adverse effects on it. In this study, Qom City in the central plateau of Iran was considered to investigate the influencing factors on heat islands. For this purpose, land surface temperature (LST) was extracted using split-window and tasseled cap transformation (TCT) algorithms from Landsat 8 bands Operational Land Imager-Thermal Infrared (OLI-TIRS) sensors. Finally, the relationship between heat islands, vegetation, humidity, and global solar ultraviolet was evaluated. The results show that urban heat islands (UHIs) have an inverse relationship with the amount of vegetation (− 0.801) and humidity (− 0.754) and a direct relationship with residential areas (0.719) and global solar ultraviolet (0.618). The expansion of the city, the insulation of the roofs of residential houses, the decrease in the density of vegetation, and the existence of barren areas in the suburbs are the main reasons for the expansion of heat islands in the suburbs of Qom City. The effects of ultraviolet radiation in the suburbs range from moderate to high, which have irreparable effects on human health in that area. The impact of ultraviolet radiation on the health of humans living in the suburbs is a concern, demanding proactive measures to educate and protect residents.</p>