Children are more susceptible to polluted air than adults. It is essential to maintain a good indoor air quality (IAQ) at school areas, where school-aged children normally stay for around 6-8 hours per day. Numerous studies have already revealed the close association between deteriorated IAQ and poorer children’s respiratory health and/or lung function growth. Moreover, the prevalence of sick building syndromes (SBSs) has been repeatedly linked to the poor IAQ, resulting in the declining academic performances of the students. Nevertheless, academic researches on local educational center’s IAQ are limited and outdated. The present study aims at widening the understanding of the attributes on air quality in local primary schools. A 2.5-years air quality measurement campaign was co...[ Read more ]

Children are more susceptible to polluted air than adults. It is essential to maintain a good indoor air quality (IAQ) at school areas, where school-aged children normally stay for around 6-8 hours per day. Numerous studies have already revealed the close association between deteriorated IAQ and poorer children’s respiratory health and/or lung function growth. Moreover, the prevalence of sick building syndromes (SBSs) has been repeatedly linked to the poor IAQ, resulting in the declining academic performances of the students. Nevertheless, academic researches on local educational center’s IAQ are limited and outdated. The present study aims at widening the understanding of the attributes on air quality in local primary schools. A 2.5-years air quality measurement campaign was conducted in 20 local primary schools from July 2012 to November 2014, covering both the cold and hot seasons.

The seasonal variations and the indoor–to-outdoor relationships were investigated. A clear seasonal difference was exhibited by particulate matters (PMs), CO₂ and airborne bacteria. The winter fine suspended particle (FSP) concentrations in local primary schools’ classrooms were found around twice of those in summer measurements. In contrast, a low indoor to outdoor ratio (I/O ratio) of 0.39 was obtained for O₃ among school measurements in both seasons. In the absence of characteristic pollutant sources, ambient air plays as an important role on local school’s air quality. The school measurement results were found closely associated with those at the closest general air monitoring stations managed by the HKEPD. A clear north-south spatial difference on the O₃ level was also identified among the studied schools after a standardization process on seasonal variations. Besides, indoor traffic-related pollutants, ultrafine particles (UFP) and NO₂, were 30-50% higher among schools close to busy motorways. Among the studied schools in this study, the traffic impacts were mainly affected by the vehicles within 250 m. And the traffic impacts were obvious among classrooms that are more proximal to the major motorways. The use of air-conditioning in hot summers limits the fresh air supply in classroom (Mean = 7.5 L/s.person), leading to a strong association of a high level of summer indoor CO₂ (> 1000 ppmv) and airborne bacteria (> 1000 cfu/m³) in the classrooms in the present study.