A recent study conducted by researchers at MacEwan University in Canada has uncovered that infrasound—sound waves below 20 Hz—may explain why certain places, like abandoned mansions, evoke feelings of fear and sadness. Although humans cannot consciously hear infrasound, their bodies can still sense it, leading to measurable stress responses and negative emotions. The study utilized a machine learning technique called 'conditional inference forest' to identify factors predicting infrasound presence. The findings revealed that participants exposed to infrasound rated music as sadder and less engaging, reported increased irritability, and exhibited elevated cortisol levels, indicating stress. Infrasound is common in urban environments, produced by sources such as ventilation systems, air conditioners, and even wind turbines, which are increasingly prevalent in India’s renewable energy sector. The researchers stress the importance of addressing infrasound pollution in spaces where people live and work, as long-term exposure could potentially impact mood and overall wellbeing. The study was published in Frontiers in Behavioural Neuroscience in 2026.