Characteristics of indoor aerosol size distribution in a gymnasium

Resumen

In this study, an indoor/outdoor monitoring programme was carried out in a gymnasium belonging to the University of Leon (Spain). The aerosol particles were measured in 31 discrete channels (size ranges) using a laser spectrometer probe (Passive Cavity Aerosol Spectrometer Probe, PMS Model PCASP-X). The air quality of the gymnasium was strongly influenced by the use of magnesia alba (MgCO3) and the number of gymnasts who were training. For this reason, aerosol size distributions under several conditions were studied: i) before sports activities, ii) activities without using magnesia alba, iii) activities using magnesia alba, iv) cleaning activities and v) outdoors. From the aerosol size composition, the aerosol refractive index and density indoors were estimated: 1.577-0.003i and 2.055 g/cm3, respectively. Using the estimated density, the mass concentration was calculated, and the evolution, for different activities, of PM1, PM2.5 and PM10 was assessed. Due to the climbing chalk and the constant process of resuspension, average PM10concentrations above 440 μg m−3 are achieved. Daily maximum concentrations ranging from 500 to 900 μg m−3 were registered in the gymnasium. As particle size determines its deposition site, according to the Spanish standard UNE 77213, equivalent to the ISO 7708:199, the inhalable and thoracic fractions were assessed and, then, the tracheobronchial and respirable fractions for healthy adults and high risk people (children, frail or sick people). The different physical activities and attendance to the sport facility have a significant influence on the concentration and size distributions observed.