# Minor influence of climbing hall characteristics on rubber-derived compound contamination highlights a need for material-level solutions

## TL;DR

Climbing halls have high levels of rubber particles from shoes, and hall design doesn't significantly reduce them, so safer shoe materials are needed.

## Contribution

The study shows that climbing hall characteristics have minor influence on rubber-derived compound contamination, highlighting the need for material-level solutions.

## Key findings

- Rubber-derived compounds were detected in every sample from 41 climbing halls.
- Hall design and operations explain little variability in rubber-derived compound levels.
- Material-level innovations are needed to replace harmful substances in climbing shoe soles.

## Abstract

Climbing shoe abrasion generates fine rubber particles, leading to elevated concentrations of rubber-derived compounds (RDCs) in airborne particulate matter and settled dust of indoor climbing halls, in some cases comparable to levels measured near high-traffic roads. Indoor climbing halls therefore represent a hotspot of RDC exposure for visitors and employees. While the health implications remain uncertain, several RDCs present in climbing halls have demonstrated toxicity in vitro and in animal studies. Previous work, limited to a small number of facilities, left open whether climbing hall characteristics can mitigate RDC contamination. Here, we analyzed more than 200 samples of settled dust and foothold powder (abrasion material) collected from 41 climbing halls across 10 countries. RDCs were detected in every sample, confirming their ubiquity. Unsupervised analyses (hierarchical clustering, principal component analysis) revealed distinct patterns in concentrations and profiles, but supervised approaches (redundancy analysis, partial least squares, univariate correlations) showed only weak associations with hall characteristics. These results demonstrate that hall design and operation exert only a minor influence on RDC levels, underscoring that effective mitigation will require material-level solutions, specifically safe and sustainable-by-design (SSbD) innovations in the material used in climbing shoe soles to replace substances of concern with safer alternatives.

Rubber-derived compounds are ubiquitous in climbing halls. Climbing hall design and operational practice explain little variability in rubber-derived compound levels, emphasizing that mitigation needs to occur at the product design level.