# Smelling Wellness: Associations Between Botanic Garden Scentscapes and Human Health Gains

## TL;DR

This study shows that spending time in botanic glasshouses with plant scents can reduce anxiety and heart rate, suggesting nature-based scentscapes can improve urban health.

## Contribution

The study introduces the concept of 'scentscapes' in botanic glasshouses as a novel nature-based intervention for urban mental and physiological health.

## Key findings

- Glasshouse exposure reduced anxiety scores and heart rate compared to a plant-free room.
- Distinct plant scent profiles were linked to therapeutic effects observed in clinical settings.
- Results suggest that aromatic plant species in urban green spaces can support public health.

## Abstract

Public health relevance—How does this work relate to a public health issue?
Given the increasing prevalence of stress-related health disorders and the continued urbanisation of populations, there is an increasing need for accessible nature-based interventions in urban environments.Accordingly, this study examines how the plant-based scent profiles found in botanic glasshouses could contribute to measurable changes in health and wellbeing outcomes.

Given the increasing prevalence of stress-related health disorders and the continued urbanisation of populations, there is an increasing need for accessible nature-based interventions in urban environments.

Accordingly, this study examines how the plant-based scent profiles found in botanic glasshouses could contribute to measurable changes in health and wellbeing outcomes.

Public health significance—Why is this work significant to public health?
Observations of reduced anxiety, negative emotions and heart-beat rate after 30 min glasshouse exposure are consistent with the previous findings from clinical studies on the health effects of scents released by plants.The identification of distinct plant scent profiles previously associated with therapeutic effects in clinical settings, highlights the potential for vegetation-rich environments to deliver meaningful physiological and psychological health benefits.

Observations of reduced anxiety, negative emotions and heart-beat rate after 30 min glasshouse exposure are consistent with the previous findings from clinical studies on the health effects of scents released by plants.

The identification of distinct plant scent profiles previously associated with therapeutic effects in clinical settings, highlights the potential for vegetation-rich environments to deliver meaningful physiological and psychological health benefits.

Public health implications—What are the key implications or messages for practitioners, policy makers and/or researchers in public health?
Differences in responses between the glasshouses suggest that the airborne compounds released by certain plant species may be associated with psychological and physiological calming.These results reinforce the importance of considering smell (scentscapes) along with sight and sound in urban green space planning and policy.

Differences in responses between the glasshouses suggest that the airborne compounds released by certain plant species may be associated with psychological and physiological calming.

These results reinforce the importance of considering smell (scentscapes) along with sight and sound in urban green space planning and policy.

This pilot study investigated whether ambient biogenic volatile organic compounds (bVOCs)—scent profiles emitted by botanic glasshouse vegetation—could contribute to quantifiable human health and wellbeing outcomes. Over 11 months in 2024 (January–December), human participant trials were conducted at the Oxford Botanic Garden to compare the physiological and psychological effects associated with spending 30 min exposures in five different vegetation-rich glasshouses, each characterised by a distinct and complex bVOCs profile, with those of a plant-free room. Pre- and post-intervention assessments were conducted on 43 participants, using the State-Trait Anxiety Inventory (STAI), heart-beat rate (beats per minute), and heart rate variability (HRV): the latter two are widely used as an index of regulation of the autonomic nervous system. Significant reductions in STAI anxiety scores and decreases in heart-beat rate were observed, while HRV indices remained stable, relative to the plant-free room, following glasshouse exposure. Distinct scent profiles in the glasshouses included compounds that have previously shown associations with therapeutic effects in clinical settings, indicating the potential of these scented vegetation-rich glasshouse environments to promote the beneficial health effects observed in this study. Overall, these findings highlight the potential public health value of aromatic plant species and the importance of incorporating them into urban green space planning and policy.