Environmental noise refers to the unwanted or harmful sound generated by human activities in outdoor environments. This can include noise from transportation (such as cars, airplanes, and trains), industrial activities, construction sites, and outdoor events. Environmental noise can have negative impacts on human health, including hearing loss, sleep disturbances, stress, and decreased cognitive performance. Research in this area focuses on monitoring and studying the sources, effects, and mitigation strategies for environmental noise pollution in order to protect human health and improve the quality of outdoor environments.