Indoor climbing and bouldering have become increasingly popular in recent years. However, special shoes that use climbers for this sport freely put in the chemicals of questionable chemicals, as researchers have now found out. These fabrics can get into the upper respiratory tract or the lungs and harm the body. In the future, operators of climbing halls should try to improve the air quality of their halls.
The German Alpine Association estimates that more than a million people in Germany regularly climb. Many use Indoor climbing halls to practice climbing and bouldering without the weather regardless of the weather. In October 2023 there were 566 artificial climbing facilities in Germany. To keep a safe grip and protect your feet, climbers wear special shoes. A special rubber sole gives you a particularly good grip – enough “grip” so as not to slip from the handles.
From handle into the lungs
The soles of the climbing shoes contain similar rubber mixtures such as car tires, but also various additives that are suspected of harming people and the environment. “The soles of climbing shoes are high -performance products, just like car tires,” explains first author Anya Sherman from the University of Vienna. “Additives are specific chemicals that make these materials more resistant and durable, they are essential for their function.”
However, the good stance friction also means that the soft sole rubs off over time and gives tiny particles. The rubber types then settle on the handles on climbing walls. “We knew the black residues on the handles in climbing halls, the abrasion of the shoe soles,” explains Sherman. “Climbing wipe it away for a better support and whirling it into the air.” Sherman and her team have now analyzed how much this abrasion is actually in the air of climbing halls.
To do this, they collected samples from dust on the ground, the abrasion on the handles in five climbing halls in Vienna and a total of four others in Switzerland, France and Spain as well as 30 shoe soles of common manufacturers. They then analyzed the amount of rubber abrasion in the samples. In addition, the researchers, with an impinger, a particle measuring device, imitate human breathing to check how many additives get from the rubber soles into the airways of climbers and employees.
Higher fabric concentration than on a busy street
The analyzes show that people in the climbing halls inhale the up to 7.8-fold of elastical material compared to street workers in the Smog-based Chinese mega cities. In addition, they take up a large amount of benzothiazole by two orders of magnitude than even the workers at Spanish industrial locations. Rubber manufacturers use the benzothiazole to accelerate the vulcanization of the rubber. In a well -attended climbing hall, Sherman and her team found 3070 micrograms of aerosol particles per cubic meter. In comparison, the air of a less well -attended climbing hall contained just 180 micrograms of aerosol particles per cubic meter.
The researchers assume that the ventilation and the design of the halls also play a role as many particles remain in the air. In her view, it would therefore be important to improve the air quality in the halls. With optimized ventilation and regular cleaning of the hall, the operators could already reduce the concentration of the floating particles in the air. Climbers could avoid peak times and buy climbing shoes that contain less additives to prevent any harmful stress, according to the research team.
Source: University of Vienna; Specialist articles: acs es & t air, DOI: 10.1021/acsestair.5c00017