Abstrakt
The school gym environment is in many aspects predisposed to high amounts of aerosol (particulate matter - PM) concentrations, which is cumulated in gym halls and re-suspended by exercising pupils during physical education (PE) lessons. PM concentrations (mainly its coarse particles) rise sharply according to the number of people exercising and the type of activity.
The aim of our study was to estimate the aerosol expo-sure for 32 children exercising with increased ventilation in Prague primary school gyms (18 girls - 10 to 14 years and 14 boys - 10 to 13 years). The indirect method of transferring heart rate to minute ventilation through the exponential regression curve was used to measure pulmonary ventilation.
HR was measured by sport-testers during PE lessons. Results of rest and ventilation load values were compared with the values of aerosol weight concentrations, measured continually by a photometer Dust Track and by the Personal Cascade Impactor Sampler.
Results have shown that the average VE multiple during exercising reached 3.8 times in the observed group. The average HR of respondents in the measured exercise unit was 150.6 beats.min-1 and the estimated x̄ VE 24.4 litres.min-1.
VE multiple values of individual pupils in an exercise unit correlate significantly (r = 0.78) with average HR values in the time unit. Aerosol concentrations reached in measured PE lessons from PM2.5 22.4 to 24.4 [μg.m-3] and from PM10 60.14 to 101.12 [μg.m-3].
If the tested pupils raised their ventilation to the estimated 3.8 times their resting value, exposure to PM exceeded the sanitary limits set by WHO guidelines for school environments. Out of 112 observed days, in three Prague primary schools, 89% of days in school gyms and 46 % of days outdoors were over this limit (under the above stated conditions of VE multiple).