| Summary: | 碩士 === 國立臺灣大學 === 環境衛生研究所 === 107 === People spend approximately 90% of their time indoors, hence the potential health impact from indoor air pollutants causes concerns. In the indoor environments, various scented products, such as essential oils, cleaners and deodorants, are often used to produce pleasant smells. Within these smelling compounds, terpenes, which are defined as the chemicals with structures made of the combinations of isoprenes, will easily react with oxidants, such as ozone, hydroxyl (OH) radicals, nitrate (NO3) radicals, or via photolysis to form several oxides. It is noteworthy that certain terpene oxides are highly allergenic, which might cause terpene-related allergy, and that they are easy to form secondary organic aerosol (SOAs). Thus, terpenes are important precursors of indoor air quality issue.
Besides, the most abundant terpenes found in our lives are α-pinene, β-pinene, 3-carene, and d-limonene, which are allergy to patients with skin disorders, risk factors to children, and irritants of skin allergy, airway irritation to general public. Hence, this study focus on the exposure of these four terpenes. As consumers apply these scented products, terpenes may emit to the air and enter human body through inhalation and dermal absorption, as well. Therefore, the exposure strategy needed to determine the exposures of terpenes from both inhalation and dermal routes.
To the best of our knowledge, in terms of personal sampling, silicon wristband may be the only tool that can capture chemicals from the air and on the skin, with affordable price, and non-toxic, not flammable, ecofriendly, and stable properties. However, most of the studies reported elsewhere yield the result in form of mass per wristband, since it is not easy to obtain quantitative data and establish the connections between the findings from silicone wristbands and environmental concentration.
To make it a better personal sampler, the design of silicone wristbands had been improved to increase their performance without influencing by the wind outside under different sampling condition. The design of these silicone wristbands are composed of 2 pieces of silicone wristbands, a rubber watch band and a 2 um PTFE membrane on the top. Two pieces of silicone wristbands are used to capture terpenes from air and human skin, respectively. The outer piece of silicone wristband exposes to the environmental air and are used to assess inhalation exposure, whereas the inner piece direct contact with skin and thus are used to assess dermal exposure.
In this study, validations were conducted to test the sampling ability of the outer silicone wristband as a passive air sampler. Silicone wristband samplers were placed in a vapor generation and exposure system for α-pinene, β-pinene, 3-carenen, and d-limonene, which was composed of a zero air generator, syringe pump, mixing chamber and exposure chamber. After exposures, all samples were extracted and analyzed with gas chromatography mass spectrometry (GC-MS).
Furthermore, wind speed was moderated and examined in the exposure chamber, and was used to estimate the sampling performance of silicone wristbands under different wind speed. It had been found that the critical wind speed for these silicone wristband samplers is 0.22 m/s. Since the wind speed due to people’s movement or normal wind outsides is higher that this critical wind speed, these samplers can perform constantly under sampling.
Besides, the silicone wristband samplers were placed in exposure system to sampling under different humidity. The sampling rate of α-pinene, β-pinene, 3-carenen, and d-limonene under 35%-90% humidity had no significant difference in the values.
Before conducting the experiment, silicone wristbands were pre-cleaned with the desorption solvent together, to decrease the variance between each wristband. After exposure, known mass of surrogate was spiked on each wristband, in order to calculate desorption efficiency for each wristband. The desorption efficiency was mainly 70-90%. The sampling rate of α-pinene, β-pinene, 3-carenen, and d-limonene under 60%, were 1.923 ml/min, 0.418 ml/min,4.162 ml/min and 6.443 ml/min, respectively.
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