| Summary: | 碩士 === 長榮大學 === 職業安全與衛生研究所 === 95 === Many studies have demonstrated that ultrafine particles are generated as a result of the reactions between monoterpene and ozone as well as other oxidants. Studies also indicated ultrafine particles may pose health hazards when inhaled. Essential oils are commonly used in indoor environments today and spa centers offering aromatherapy service are emerging. However information regarding the effects of essential oils on indoor air quality, especially the ultrafine particles generated from the secondary reaction between ozone and essential oils is very limited. The first part of this study was conducted in a controlled environmental chamber to investigate the capability of different essential oils to generate secondary organic aerosol (SOA). The second part of this study was to investigate the particle concentration in three spa centers offering aromatherapy. The results of the chamber study showed that fragrant essential oils produced much more SOA than herbal essential oils when ozone (120 ppb) was present in the chamber. Tea tree essential oil produced as high as 1.9×106 particles/cm3, the highest among the fragrant essential oils. The analysis of chemical constituents of the essential oils tested suggested that fragrant essential oils contain more precursors, such as monoterpense, of SOA than herbal essential oils. The results from spa centers sampling indicated that particle number concentration increased as aromatherapy started. However, particle number concentration in each particle size range varied among the three centers, partially because of the difference in indoor layout and ventilation condition. Moreover, concentration of total volatile organic compounds (TVOCs) reached 4500 ppb while aromatherapy was performed. Due to the fact that ultrafine particles and VOC are generated when essential oils are used in indoor environments, more attention should be paid on their effects on indoor air quality.
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