Phase transitions and heterogeneous chemistry of tropospheric aerosols

总的来说，我们的研究将侧重于大气化学，总体目标是提高对大气中重要过程的认识。我们拟议研究的第一部分将探索大气气溶胶粒子从液体转化为固体的条件，反之亦然。 换句话说，我们将探讨气溶胶粒子的相变，是大气的重要性。 在这些研究中，我们将重点关注与自由对流层相关的温度下的混合有机-无机颗粒，自由对流层是高度约1公里至18公里的大气区域。颗粒相（即固体或液体）的知识对于预测颗粒的反应性以及颗粒对气候的影响是必要的。我们的实验室研究对于预测大气中卷云的形成也很重要。 我们提出的研究的第二部分将探讨气相物质和气溶胶颗粒之间的反应，称为非均相化学。 具体研究的反应包括N2 O 5和涂有有机膜的水溶性气溶胶颗粒之间的反应以及NO3自由基与有机颗粒之间的反应。 从这些研究中获得的信息可能会导致改善对大气中N2 O 5，NO3和O3浓度的预测。 我们的研究对于预测大气中有机颗粒的寿命以及预测大气中丰富的多环芳烃等有毒物质的命运也可能很重要。

In general our research will focus on atmospheric chemistry with an overall goal of improving the understanding of important processes in the atmosphere.The first part of our proposed research will explore the conditions at which atmospheric aerosol particles transform from liquid to solid and vice versa.  In other words, we will explore phase transitions of aerosol particles that are of atmospheric importance.  In these studies we will focus on mixed organic-inorganic particles at temperatures relevant for the free troposphere, which is the region of the atmosphere between approximately 1 km and 18 km in height. Knowledge of the particle phase (i.e. solid or liquid) is necessary to predict the reactivity of particles and also the impact of particles on climate. Our laboratory studies may also be important for predicting the formation of cirrus clouds in the atmosphere.  The second part of our proposed research will explore reactions between gas-phase species and aerosol particles, termed heterogeneous chemistry.  Specific reactions to be studied include the reaction between N2O5 and aqueous aerosol particles coated with organic films and NO3 radicals with organic particles.  Information from these studies may lead to improved predictions of N2O5, NO3, and O3 concentrations in the atmosphere.   Our research may also be important for predicting the lifetime of organic particles in the atmosphere and for predicting the fate of toxic species such as polycyclic aromatic hydrocarbons, which are abundant in the atmosphere.