摘要
粉筆-黑板教學過程產生之粉筆微粒可能會危害老師健康及影響學生上課學習，因此本研究之目的為探討老師使用無灰粉筆教學之粉塵暴露及粉筆微粒對室內空氣品質之影響。本研究選定一間上課教室及五種不同通風條件，進行無灰白色粉筆書寫及擦拭黑板，使用粉塵粒徑分析儀及氣膠偵測器量測講台區及教室內外之微粒濃度，並配合掃描式電移動度微粒粒徑分析儀量測粒徑分布。結果顯示無灰粉筆教學會產生大量粉塵，造成講台區附近質量濃度增加，其中可吸入性及胸腔性粉塵濃度約佔90%，可呼吸性粉塵濃度約佔10%。微粒質量濃度主要是以粗粒徑(PM2.5-10)貢獻為主，雖然細微粒所佔比例較小，但由粒徑分布顯示粉筆會大量增加次為米及奈米微粒數目。教室內不同通風條件會造成高濃度粉筆微粒出現位置有所差異，但微粒主要分布在講台區附近。粉筆微粒確實會增加室內空氣品質惡化，室內主要粗微粒來源為粉筆粉塵，而細微粒來源則會受到粉筆、室內空氣擾動及室外空氣的影響。本研究證明無灰粉筆教學不但會產生粗微粒，也會產生細微粒與奈米微粒，擦拭黑板期間更是明顯，此結果可供使用粉筆教學的老師與上課學生做為教室內空氣品質改善與防護粉塵的參考。
關鍵字：無灰粉筆、氣膠、通風、室內空氣品質
ABSTRACT
The generated particles during the period of chalks-board teaching could damage teacher’s health and affect students’ learning efficiency. The aims of this study were to explore teacher’s exposure to dust using anti-dust chalk teaching and the effects of chalk dust on indoor air quality. In this study, a classroom with five different ventilation conditions was selected to conduct the activities of writing on and cleaning the board. The mass concentrations of particles were measured by a dust size analyzer in platform area and one aerosol monitor at inside and outside of classroom. The size distribution of particles was also measured using a scanning mobility particle sizer. The results indicated that anti-dust chalks could generate large quantity of dust and increase significantly the mass concentrations in the neighbor of platform area during class time. The concentrations of inhalable and thoracic dust were about 90% of the mass concentration of suspended chalk particles, and the other 10% was repairable dust. The coarse particles (PM2.5-10) were the major contributor to the mass concentration of dust. The proportion of fine particles was small. However, the size distributions of particles showed that chalks could increase a large number of sub-micron and nano-particles significantly. Varied with different ventilation conditions, the high concentrations of chalk particles appeared at different locations of the classroom. However, most chalk dust presented in the vicinity of platform area that indeed deteriorated indoor air quality. The major source of coarse particles was chalk dust. The source of fine particles was affected by chalk dust, disturbance of indoor air, and outdoor air. This study demonstrated that teaching used anti-dust chalks could generate coarse particles, fine and nano-particles. Those generated obviously during the period of wiping board. The results could provide a reference of improving indoor air quality and protecting against particles to teachers and students in classroom.
Keywords: Anti-dusting chalk; Aerosol; Ventilation; Indoor air quality
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