Liquid crystal monomers (LCMs) are synthetic chemicals widely used in liquid crystal displays such as televisions and smartphones and have recently been detected in indoor dust. Despite extensive use, the atmospheric fate of LCMs is unknown. Here, the heterogeneous OH oxidation of LCMs was studied by exploring the kinetics and mechanisms of 1-ethyl-4-(4-(4-propylcyclohexyl)phenyl)benzene (EPPB) and 4′′-ethyl-2′-fluoro-4-propyl-1,1′:4′,1′′-terphenyl (EFPT) coated onto ammonium sulfate particles. The measured heterogeneous rate constants for EPPB and EFPT were (7.05 ± 0.46) × 10^–13 and (4.67 ± 0.25) × 10^–13 cm³ molecule^–1 s^–1 ,respectively, equivalent to atmospheric lifetimes of up to 25 and 38 days. These lifetimes are significantly longer than previously predicted values (<1 day) for these LCMs, indicating that they are much more persistent in air than predicted, with the potential to undergo long-range transport. Furthermore, 66 transformation products from the heterogeneous photooxidation of these LCMs were identified for the first time. Given the known toxicity of the parent LCMs, their measured persistence in the atmosphere, and the demonstrated complexity of their products, the present results not only underscore the need to quantify the levels of LCMs in ambient air, but also suggest that the presence of their transformation products should not be ignored when assessing the risks of airborne LCMs.

中文翻译：

---

颗粒状液晶单体的大气OH氧化化学：空气中新兴的持久性有机污染物

液晶单体（LCM）是广泛用于电视和智能手机等液晶显示器的合成化学品，最近在室内灰尘中被检测到。尽管得到了广泛使用，但LCM的大气命运仍是未知的。在此，通过探索1-乙基-4-（4-（4-（4-丙基环己基）苯基）苯（EPPB）和4''-乙基-2'-氟-4的动力学和机理研究了LCM的异质OH氧化-丙基-1,1'：4'，1''-三联苯（EFPT）涂覆在硫酸铵颗粒上。EPPB和EFPT的测得异质速率常数为（7.05±0.46）×10 ^–13和（4.67±0.25）×10 ^–13 cm ³分子^–1 s ^–1分别相当于25年和38天的大气寿命。这些寿命比这些LCM的先前预测值（<1天）要长得多，这表明它们在空气中的持久性比预测的要持久得多，并且有可能进行远距离运输。此外，首次从这些LCM的异质光氧化中鉴定出66种转化产物。考虑到母体LCM的已知毒性，其在大气中的持久性以及产品的复杂性，目前的结果不仅强调了量化周围空气中LCM含量的必要性，而且还表明了它们的存在。在评估机载LCM的风险时，不应忽略任何转换产品。