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Using Silicone Wristbands as Personal Samplers to Monitor the Exposures of Airborne Terpenes
indoor air quality,terpene,silicone wristband,exposure assessment,gas generation and exposure system,
|Publication Year :||2019|
本研究在暴露腔中使用風扇來調節風速，並以風速計量測矽膠手環的表面風速，用以驗證矽膠手環採樣器在不同風速下的採樣表現。實驗證實，矽膠手環採樣器的臨界風速為0.22 m/s，且在一般的環境風速及人們日常活動所造成的風速皆高於0.22 m/s，意即不論是日常配戴或作為環境採樣，矽膠手環皆會有一致的採樣表現。
本研究在進行暴露實驗前，將20片矽膠片以脫附溶劑一起清洗，用以降低同批次實驗矽膠片之間的變異。而矽膠片暴露後，亦會添加已知質量的擬似標準品，使其完整吸收後在進行脫附，用以計算每片矽膠的脫附效率。本研究中矽膠手環的脫附效率主要為70-90％；採樣率的部分，以60%濕度來說，α-蒎烯、β-蒎烯、蒈烯和d-檸檬烯的採樣率則分別為1.923 ml/min、0.418 ml/min、4.162 ml/min以及6.443 ml/min。
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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