Natural Volatile Organic Compounds (NVOCs) Are Greater and More Diverse in UK Forests Compared with a Public Garden

Abstract

Forest bathing is based upon a Japanese practice known as Shinrin–Yoku and is a nature-based therapy involving mindful walks through ancient woodland to reduce stress and anxiety. One proposed mechanism behind the effectiveness of Forest bathing is based on the potential mental and physical health benefits of the natural volatile organic compounds (NVOCs) that fill the forest understory. Surprisingly little is known about the concentrations and diversity of plant NVOCs in ambient air particularly in the UK and this study aims to increase that knowledge. Air samples were collected in July 2022 in a UK forest and compared with samples from a walled garden environment. The samples were collected over a 2 h time period and analysed using GC-MS and showed clear differences in the chemical composition of the air. This study revealed NVOCs including limonene, carvone, terpenes, terpenoids and sesquiterpenoids were present within a UK forest but were either not present or present at little to low levels in the control setting of a walled garden. This study also found that the typical 2 h duration of a Forest bathing session was a long enough sampling period to detect these NVOCs, indicating that Forest bathers could benefit from exposure to NVOCs.