Climbers and workers at indoor climbing walls may be breathing in large doses of potentially toxic rubber additives, according to a study reporting that the air and dust in climbing centres contain high levels of rubber particles from the soles of climbing shoes.
These soles are typically made from the same materials as car tyres, which are a major source of air pollution.聽Dust produced by the wear of rubber tyres on cars and trucks is breathed in by people on or near roads, and thus enters their lungs and guts.
The rubber in a tyre can contain up to 1000 additives, says at the University of Vienna, Austria. The effects of many of these compounds are unknown, but some are toxic. A 2020 study found that a derivative of the tyre additive 6PPD was polluted by road run-off.
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鈥淲e are testing right now how much these additives influence your gut and your lung,鈥� says Hofmann.
In a study that has yet to be peer-reviewed, Hofmann and his colleagues took air and dust samples from two climbing gyms in Austria and further dust samples from another two halls. They found high levels of particulate air pollution, exceeding World Health Organization guidelines.
The team members found nine of the 15 rubber additives they tested for in the air samples and 12 out of 15 in the dust samples. The detected compounds included 6PPD.
They then estimated how much of these additives climbers might breathe in and found that the amount would be higher than standing next to a busy road. 鈥淲e highlight that exposure from indoor climbing halls exceeds every other exposure source known to date, including from such contaminated environments as roadsides in megacities,鈥� they write in a paper posted on a preprint server. Hofmann declined to discuss the findings before they have been formally published.
Next, the team tested the soles of 30 different makes of climbing shoes. They found many contained some of the 15 additive compounds in the soles, with one sole containing all 15, suggesting that climbing shoes are the main source of the detected rubber additives.
鈥淯ntil rubber becomes safer, potential strategies to minimize exposure in climbing halls should also be considered, such as more frequent cleaning, mobile and stationary HEPA air filters, or banning of certain shoe models,鈥� write the researchers.
ChemRxiv
