Indoor aerosol size distribution in climbing gyms
The long-term health effects of chalk dust in gyms is a constant topic of study. Current consensus is that climbing chalk dust has a definite short-term effect on health and performance, but no long-term dangers leading to e.g. silicosis have been observed because the particle size of MgCO3 is essentially too big to do long-term damage to the respiratory system. This study looks into aerosol distribution of dust in gyms at the PM10 (long-term safe) level. This post is part of a series where we highlight the existing research around chalk.
Reading Note: Particulate matter is measured in PM values. E.g. PM10 corresponds to the fraction of particles with an aerodynamic diameter smaller than 10 µm. PM values start to become dangerous as they approach “fine dust” levels, i.e. PM2.5
Abstract, emphasis ours: In this study, an indoor/outdoor monitoring program was carried out in a gymnasium at the University of Leon, Spain. The main goal was a characterization of aerosol size distributions in a university gymnasium under different conditions and sports activities (with and without magnesia alba) and the study of the mass fraction deposited in each of the parts of the respiratory tract. The aerosol particles were measured in 31 discrete channels (size ranges) using a laser spectrometer probe. Aerosol size distributions were studied under different conditions: i) before sports activities, ii) activities without using magnesia alba, iii) activities using magnesia alba, iv) cleaning procedures, and v) outdoors. The aerosol refractive index and density indoors were estimated from the aerosol composition: 1.577-0.003i and 2.055 g cm(-3), respectively. Using the estimated density, the mass concentration was calculated, and the evolution of PM1, PM2.5 and PM10 for different activities was assessed. The quality of the air in the gymnasium was strongly influenced by the use of magnesia alba (MgCO3) and the number of gymnasts who were training. Due to the climbing chalk and the constant process of resuspension, average PM10 concentrations of over 440 μg m(-3) were reached. The maximum daily concentrations ranged from 500 to 900 μg m(-3). Particle size determines the place in the respiratory tract where the deposition occurs. For this reason, the inhalable, thoracic, tracheobronchial and respirable fractions were assessed for healthy adults and high risk people, according to international standards. The estimations show that, for healthy adults, up to 300 μg m(-3) can be retained by the trachea and bronchi, and 130 μg m(-3) may reach the alveolar region. The different physical activities and the attendance rates in the sports facility have a significant influence on the concentration and size distributions observed.
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