利用矽膠手環作為個人萜烯暴露的採樣器

Abstract

根據統計，人們大約有90％的時間待在室內，因此室內環境的空氣議題對健康的潛在影響值得被關注。尤其在室內環境中，經常使用精油，清潔劑和除臭劑等的香味產品來產生令人放鬆的氣味。在這些有氣味的化合物中，萜烯(terpene)被定義為具有異戊二烯組合結構的化學物質，很容易與空氣中的氧化劑反應，如臭氧，羥基自由基（OH），硝酸鹽自由基（NO3），或通過光解形成多種氧化物。值得注意的是，部分萜烯氧化物具有高度致敏性，可能引起與萜相關的過敏，且它們也易於形成室內的二次有機氣氣膠（SOA）。因此，萜烯是IAQ問題的前驅物之一。 此外，我們的生活中最常見的萜烯α-蒎烯(α-pinene)、β-蒎烯(β-pinene)、蒈烯(3-carene)和d-檸檬烯(d-limonene)，除了萜烯本身對於皮膚敏感族群的致敏性強，以及是孩童免疫反應的危害因子，對於一般大眾也會刺激呼吸系統與皮膚黏膜。因此，本研究選定此四項物質作為暴露評估的議題。而當消費者使用這些香味產品時，揮發於空氣中或塗抹於皮膚上的萜烯可能透過吸入或皮膚暴露途徑進入人體，而日後能否同時評估吸入與皮膚的暴露，也成為本研究選定暴露評估採樣器時最重要的因素。 在個人採樣方法中，矽膠手環可能是目前唯一能採樣來自空氣和皮膚上的化學物質的工具，又是個經濟實惠、無毒、不易燃、環保且穩定的材料。然而，目前關於矽膠手環作為採樣器的文獻大多都以每個腕帶的採集到多少質量的化學品的形式呈現，無法取得可以定量的濃度數據並建立矽膠手環結果與環境濃度之間的關係。 為了使其成為更好的個人採樣器，在本研究針對矽膠手環的設計進行改良，以降低外界風場對於手環採樣的影響，使其在不同環境風速下能有一致的採樣表現。改良後的矽膠手環由兩片矽膠片、橡膠腕帶和2微米PTFE膜組成。兩塊矽膠片分別用於採集空氣中或人體皮膚上的萜烯：較外側的矽膠片暴露於環境空氣中，用於評估吸入暴露，而較內側的矽膠片則直接接觸皮膚，因此用於評估皮膚暴露。 本次的實驗針對外側矽膠手環，作為被動式個人採樣器定量環境濃度，進行一系列的驗證。矽膠手環採樣器被放置於已知濃度α-蒎烯、β-蒎烯、蒈烯和d-檸檬烯的暴露系統中；而此系統則由零級氣體產生器、注射幫浦、混合腔和暴露腔等部分組成。矽膠手環暴露已知濃度及時間後，會接著使用脫附溶劑提取手環上的化學品並用氣相層析質譜儀（GC/MS）進行分析。 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。 此外，本研究亦將矽膠手環採樣器放置於暴露腔，製造不同相對濕度的環境使其暴露，再繪製出不同相對濕度下α-蒎烯、β-蒎烯、蒈烯和d-檸檬烯的採樣率。並使用ANCOVA統計檢定，檢定採樣率在35%到90%濕度環境下，其採樣率沒有顯著之差異。 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.