Lyles School of Civil Engineering, Purdue University, West Lafayette, Indiana 47907, United States.
O'Neill School of Public and Environmental Affairs, Indiana University, Bloomington, Indiana 47405, United States.
Environ Sci Technol. 2023 Dec 5;57(48):19999-20009. doi: 10.1021/acs.est.3c05156. Epub 2023 Nov 16.
Cyclic volatile methyl siloxanes (cVMS) are ubiquitous in hair care products (HCPs). cVMS emissions from HCPs are of concern, given the potential adverse impact of siloxanes on the environment and human health. To characterize cVMS emissions and exposures during the use of HCPs, realistic hair care experiments were conducted in a residential building. Siloxane-based HCPs were tested using common hair styling techniques, including straightening, curling, waving, and oiling. VOC concentrations were measured via proton-transfer-reaction time-of-flight mass spectrometry. HCP use drove rapid changes in the chemical composition of the indoor atmosphere. cVMS dominated VOC emissions from HCP use, and decamethylcyclopentasiloxane (D5) contributed the most to cVMS emissions. cVMS emission factors (EFs) during hair care routines ranged from 110-1500 mg/person and were influenced by HCP type, styling tools, operation temperatures, and hair length. The high temperature of styling tools and the high surface area of hair enhanced VOC emissions. Increasing the hair straightener temperature from room temperature to 210 °C increased cVMS EFs by 50-310%. Elevated indoor cVMS concentrations can result in substantial indoor-to-outdoor transport of cVMS via ventilation (0.4-6 tons D5/year in the U.S.); thus, hair care routines may augment the abundance of cVMS in the outdoor atmosphere.
环状挥发性甲基硅氧烷（cVMS）普遍存在于头发护理产品（HCPs）中。考虑到硅氧烷对环境和人类健康的潜在不利影响，HCPs 中的 cVMS 排放令人担忧。为了描述 HCPs 使用过程中 cVMS 的排放和暴露情况，在一栋住宅建筑中进行了现实的头发护理实验。使用常见的头发造型技术，如拉直、卷曲、波浪和上油，对基于硅氧烷的 HCPs 进行了测试。通过质子转移反应飞行时间质谱法测量了挥发性有机化合物浓度。HCP 的使用使室内大气的化学成分迅速发生变化。cVMS 主导了 HCP 使用过程中的 VOC 排放，并且十甲基环五硅氧烷（D5）对 cVMS 排放的贡献最大。头发护理过程中 cVMS 的排放因子（EF）范围为 110-1500 mg/人，受 HCP 类型、造型工具、操作温度和头发长度的影响。造型工具的高温和头发的高表面积增强了 VOC 的排放。将直发器的温度从室温升高到 210°C，可使 cVMS 的 EF 增加 50-310%。升高的室内 cVMS 浓度可通过通风导致大量 cVMS 从室内向室外输送（在美国每年有 0.4-6 吨 D5）；因此，头发护理程序可能会增加户外大气中 cVMS 的丰度。
