Particle Resuspension in School Gyms during Physical Activities

Abstract

The aim of this work was to quantify the exposure of children to particle resuspension in school gyms. In fact, although moderate standard aerobic activity is suggested for good health, adverse health effects could affect people exercising in micro-environments with ambient pollution. Overall, 12 micro-environments were chosen and analyzed in a 3-month experimental campaign. The different fractions of particulate matter (PM) were measured by means of photometers, calibrated for the specific aerosols studied through gravimetric samplers, whereas particle number distributions in the 0.5-20 μm range were continuously measured using an Aerodynamic Particle Sizer (APS) spectrometer. High PM concentration levels were measured in school gyms compared to outdoor values. The dominant source is the particle resuspension produced by the activity of exercising pupils and, among the various PM fractions, the effect on coarse particles (PM 10-2.5 ) was found to be the most important, with the related emissions factors measured in the range of 1.5-8.9 mg/min. During school activities, under natural ventilation conditions, the average coarse particle concentrations at the 12 school gyms investigated were found to be 4.8 ± 2.0 times higher than the background (outdoor) values. The key parameters are the number and intensity of the physical activities, which can be characterized by the total energy used by the students. Therefore, this study provides useful data on the exposure of students to airborne particles during periods of physical activity in gyms with natural ventilation.

Characterization, Fate, and Re-Suspension of Aerosol Particles (0.3-10 µm): The Effects of Occupancy and Carpet Use

“…In the same study, the I/O ratio was below 0.5 with the indoor PM 10-2.5 varied between 0.5-4.9 µg m -3 during weekends and holidays. In another study, Buonanno et al (2012) confirmed that the PM 10-2.5 emission factors in the range of 1.5-8.9 mg min -1 during exercising activities of pupils inside a school gym. These re-suspension rates were slightly higher than those presented by Ferro et al (2004) as 0.03-0.5 mg min -1 for PM 2.5 and 0.1-1.4 mg min -1 for PM 5 .…”

“…For example, re-suspension is affected by human foot motion such as walking and foot tapping, which also redistribute particulate matter on a surface (Kubota and Higuchi, 2013). A strong correlation appears between the number of individuals and the particle re-suspension (Buonanno et al, 2012). Moreover, carpets are potentially more significant with higher resuspension rates in comparison to smooth and bare floors (Shaughnessy and Vu, 2012).…”

“…These re-suspension rates were slightly higher than those presented by Ferro et al (2004) as 0.03-0.5 mg min -1 for PM 2.5 and 0.1-1.4 mg min -1 for PM 5 . The differences between Buonanno et al (2012) and Ferro et al (2004) are possibly due to the difference in the considered particle size range.…”

“…Furthermore, human mechanical activities indoors increase the concentration of particles by re-suspending them to become airborne again. Hence, the attention is drawn towards school gyms and children care centers (e.g., Ferro et al, 2004;Buonanno et al, 2012).…”

Particulate Air Pollution at Schools: Indoor-Outdoor Relationship and Determinants of Indoor Concentrations

“…The main reason of high concentration of PM 1.0 in classrooms was resuspension of of PM due to the students' movements. Buonanno et al (2012b) characterized there suspension of particles in school gyms and concluded that student activity was the main predictor of particle resuspension and among the various PM fractions, coarse particles (PM 2.5 and PM 10 ) were found to be the most relevant. Guo et al (2010) did not find any influence on indoor PM 2.5 concentrations of the number of students in the classroom, which is consistent with our findings.…”