Effects of plant aromas on stress recovery and brain activity in university students

The olfactory environment is an important component of the indoor environment, closely related to health, comfort, and performance. This study aims to explore how different plant aromas (peppermint, rose, and lavender) impact stress recovery and electroencephalography (EEG) in university students. EEG signals were recorded from 40 students during the transition from stress-inducing to aroma exposure, analyzing global power (Power total), neural avalanche parameters, and network features of brain. The results indicate that plant aroma exposure improves subjective perception and positive emotions, reducing total mood disturbance by 28.97-30.37 %. Power total significantly decreased by 0.06-0.75 mu v2, with oscillatory activity more rapidly returning to a comfortable state. Plant aromas significantly enhanced the brain's self-organized criticality. Compared to rose and lavender, peppermint improved the brain's order-disorder balance by 21.79-28.74 %. Rose and lavender had a more positive impact on avalanche activity in females than males. Plant aromas enhanced brain function connectivity, increasing clustering coefficient, global and local efficiency by 4.42-10.36 %, 0.12-8.27 %, and 1.11-2.60 %, respectively, while reducing shortest path length by 1.56-9.99 %, thus improving brain information exchange capabilities. There were close correlations between aroma perception, emotions, and brain oscillatory activity, avalanche activity, and brain networks. This study provides effective indicators for evaluating the effects of aromas on stress recovery and provides fresh insights into the dynamic activities of the brain in indoor olfactory environments.