CAREER: Interplay of Particle Phase State and Thermodynamic Mixing in Secondary Organic Aerosol Formation and Partitioning

森林和人类活动排放的反应性气体通过复杂的过程转化为细颗粒物。目前的模型无法预测这种二次颗粒物的产生和颗粒物的性质，限制了我们评估对区域空气质量和水循环的影响的能力。该项目将开发一个详细的第一性原理模型，并通过测量对其进行校准，以预测对流风暴中二次细颗粒的产生、它们的性质及其对冰和云形成的影响。教育部分将开发一个基于网络的交互式计算化学模型，以告知和吸引学生进行大气研究。研究将利用气溶胶和云中气体-颗粒相互作用的主要化学机制和动力学多层模型，明确解决颗粒表面和整体的相敏反应和质量传输。这一新模型将受到由有机气体形成的二次有机气溶胶(SOA)的大小、可分解颗粒相和化学成分的实验室数据的限制。当我们从异戊二烯(生物成因)到萘(人为)有机气体时，这种形成机制是如何转变的，以及SOA的性质是如何变化的，我们将进行研究，以获得分子水平的见解。模拟将扩展到相对湿度、温度和上升气流速度的对流区域，这些对流区域涉及SOA颗粒的冰核路径，并与最近的实验室测量结果进行比较。

Forests and anthropogenic activities emit reactive gases that convert to fine particles by complex processes. Current models are unable to predict this secondary particle production and the particle properties limiting our ability to assess impacts on regional air quality and water cycle. This project will develop a detailed first principles model and calibrate it with measurements to predict secondary fine particle production, their properties and their impacts on ice and cloud formation in convective storms. The educational component will develop a web based interactive computational chemistry model to inform and attract students to atmospheric research.The research will harness a master chemical mechanism and a kinetic multi-layer model of gas-particle interactions in aerosols and clouds that explicitly resolves the phase sensitive reactions and mass transport at the particle surface and bulk. This new model will be constrained by laboratory data on size resolved particle phase and chemical composition of secondary organic aerosol (SOA) formation from organic gases. How this formation mechanism transitions and the SOA properties change as we go from isoprene (biogenic) to naphthalene (anthropogenic) organic gases will be investigated to gain molecular level insight. The simulations will be extended to convective regimes of relative humidity, temperatures and updraft velocities that involve ice-nucleation pathways for SOA particles and compared to recent laboratory measurements.