Faculty of Science, Institute for Environmental Studies, Charles University in Prague, Albertov 6, 128 43, Prague 2, Czech Republic.
Environ Sci Pollut Res Int. 2011 May;18(4):598-609. doi: 10.1007/s11356-010-0405-0. Epub 2010 Oct 24.
It has been noticed many times that schools are buildings with high levels of particulate matter concentrations. Several authors documented that concentrations of particulate matter in indoor school microenvironments exceed limits recommended by WHO namely when school buildings are situated near major roads with high traffic densities. In addition, exercise under conditions of high particulate concentrations may increase the adverse health effects, as the total particle deposition increases in proportion to minute ventilation, and the deposition fraction nearly doubles from rest to intense exercise.
Mass concentrations of size-segregated aerosol were measured simultaneously in an elementary school gym and an adjacent outdoor site in the central part of Prague by two pairs of collocated aerosol monitors-a fast responding photometer DusTrak and a five stage cascade impactor. To encompass seasonal and annual differences, 89 days of measurements were performed during ten campaigns between 2005 and 2009.
The average (all campaigns) outdoor concentration of PM(2.5) (28.3 μg m(-3)) measured by the cascade impactors was higher than the indoor value (22.3 μg m(-3)) and the corresponding average from the nearest fixed site monitor (23.6 μg m(-3)). Indoor and outdoor PM(2.5) concentrations exceeded the WHO recommended 24-h limit in 42% and 49% of the days measured, respectively. The correlation coefficient (r) between corresponding outdoor and indoor aerosol sizes increased with decreasing aerodynamic diameter of the collected particles (r = 0.32-0.87), suggesting a higher infiltration rate of fine and quasi-ultrafine particles. Principal component analysis revealed five factors explaining more than 82% of the data variability. The first two factors reflected a close association between outdoor and indoor fine and quasi-ultrafine particles confirming the hypothesis of high infiltration rate of particles from outdoors. The third factor indicated that human activity is the main source of indoor emission of coarse particles. The fourth factor involved only outdoor variables showing the resuspension of coarse ambient aerosol on dry and warm days without its seeming effect on the indoor coarse PM levels. Having in mind that high concentrations of both fine and coarse aerosol were frequently observed in the studied space, our results suggest that indoor exercise in polluted urbanized areas may increase the overall exposure and thus represent a potential health risk to young individuals during physical education at schools.
人们多次注意到学校是颗粒物浓度很高的建筑物。有几位作者记录到，当学校建筑物位于交通密度很高的主要道路附近时，室内学校微环境中的颗粒物浓度超过了世界卫生组织（WHO）建议的限值。此外，在高颗粒物浓度下运动可能会增加不良健康影响，因为总颗粒物沉积量与分钟通气量成比例增加，而从休息到剧烈运动时，沉积分数几乎增加一倍。
通过两对气溶胶监测仪——快速响应光度计 DusTrak 和五阶级联冲击式采样器，在布拉格中心的一所小学体育馆和相邻的室外场地同时测量了大小分离的气溶胶的质量浓度。为了涵盖季节性和年度差异，在 2005 年至 2009 年期间进行了十次测量活动，共进行了 89 天的测量。
级联冲击式采样器测量的（所有测量活动的）平均室外 PM（2.5）浓度（28.3μg/m（-3））高于室内值（22.3μg/m（-3））和最近固定站点监测器的相应平均值（23.6μg/m（-3））。室内和室外 PM（2.5）浓度分别在 42%和 49%的测量日超过了世界卫生组织建议的 24 小时限值。在收集的颗粒的空气动力学直径减小的情况下，相应的室外和室内气溶胶粒径之间的相关系数（r）增加（r=0.32-0.87），表明细颗粒和准超细微粒的渗透速率较高。主成分分析揭示了五个解释超过 82%数据可变性的因素。前两个因素反映了室外和室内细颗粒和准超细微粒之间的密切关联，证实了颗粒从室外渗透的高速率假设。第三个因素表明，人类活动是室内粗颗粒排放的主要来源。第四个因素仅涉及室外变量，表明在干燥和温暖的天气条件下，粗环境气溶胶会重新悬浮，但似乎对室内粗 PM 水平没有影响。考虑到在研究区域中经常观察到高浓度的细颗粒和粗颗粒，我们的结果表明，在污染的城市化地区进行室内运动可能会增加整体暴露量，从而对学校体育教育期间的年轻个体构成潜在的健康风险。
