Effects of Green Environment Exposure on Stress-Related Human Skin Gas Emissions

Urban living is associated with multiple environmental and psychosocial stressors, and urban greening has been promoted as a nature-based approach to improve health and well-being. However, the effects of green space exposure on dermal emissions of human skin gases, which may reflect physiological responses to stress, remain poorly understood. In this study, a randomized crossover design was used to investigate changes in skin gas emissions following stress and subsequent recovery. Thirteen healthy participants underwent standardized stress induction, followed by a 1-h rest period in either a green space within Ikuta Ryokuchi Park, Japan or an indoor meeting room. Skin gases were collected from the forearm using passive flux samplers, and dermal emission fluxes of stress-related compounds (ammonia and allyl mercaptan) and plant-derived monoterpenes (α-pinene, β-pinene, and limonene) were quantified. Resting in the green space significantly reduced dermal emissions of ammonia and allyl mercaptan, while increasing monoterpene levels. These results suggest that green space exposure modulates skin gas profiles in association with stress reduction, potentially influenced by inhaled monoterpenes. Skin gas analysis may provide a non-invasive approach for assessing physiological responses to environmental exposure.