Suppression of New Particle Formation by Isoprene in Non-Pristine Mixed Forest Environments

在NSF化学部环境化学科学计划的支持下，位于亨茨维尔的亚拉巴马大学（UAH）的Shanhu Lee和Bernhard Vogler及其研究生将进行实验室动力学研究，以调查与异戊二烯（一种非常重要的生物源碳氢化合物）在森林地区大气中抑制新颗粒形成（NPF）相关的化学机制。 NPF对全球云凝结核的产生有重要贡献，影响云和气候。 最近的实验室研究表明，异戊二烯抑制生物源的新颗粒的形成，但这些研究大多限于模拟原始森林条件的条件。 这项研究的重点是在美国的混合落叶林密切相关的条件，包括生物萜烯和各种污染物。 科学发现将被纳入UAH的外展计划，以向从K-12到普通公众的多个年龄组传达气候和环境问题。由Lee和Vogler团队开发的串联气溶胶成核和生长增强管（Tandem Aerosol Nucleation and Growth Enhancement Tubes）系统，用于进行涉及Terrain产生的HOM的多组分成核和生长（高度氧化的有机分子）、硫酸、氨、胺和NOx。 TANGENT系统将允许团队在受控的实验条件下独立研究新粒子的成核和随后的生长。 气相成核前体，气溶胶的大小，和颗粒相的化学成分将测量一系列国家的最先进的化学和气溶胶仪器。这些研究将是迄今为止最全面的实验室观察之一，以研究异戊二烯在非原始混合落叶林条件下以及在广泛的温度和相对湿度条件下对新颗粒成核与生长的作用。这项基础研究有望为这种重要的生物源挥发性有机化合物异戊二烯在云凝结相关颗粒形成中的作用以及气候条件提供新的见解。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Environmental Chemical Sciences Program in the Division of Chemistry at NSF, Shanhu Lee and Bernhard Vogler at the University of Alabama in Huntsville (UAH) and their graduate students will conduct laboratory kinetics studies to investigate chemical mechanisms related to the suppression of new particle formation (NPF) by isoprene, a very important biogenic hydrocarbon, in the atmosphere in forested areas. NPF contributes significantly to global cloud condensation nuclei production, impacting clouds and climate. Recent laboratory studies have demonstrated that isoprene suppresses biogenic new particle formation, but these studies were mostly limited to the conditions that mimic pristine forest conditions. This study focuses on conditions that are closely relevant to the mixed deciduous forests in the United States and include both biogenic terpenes and various pollutants. The scientific findings will be incorporated into outreach programs at UAH to communicate climate and environmental issues to multiple age groups ranging from K-12 to the general public.This project will employ a dual-flow tube system known as the TANGENT (Tandem Aerosol Nucleation and Growth ENvironment Tubes) system developed by the Lee and Vogler team to conduct multi-component nucleation and growth involving terpene-produced HOMs (highly oxygenated organic molecules), sulfuric acid, ammonia, amines, and NOx. The TANGENT system will allow the team to study nucleation and the subsequent growth of new particles independently under controlled experimental conditions. Gas-phase nucleation precursors, aerosol size, and particle-phase chemical composition will be measured with a series of state-of-the art chemical and aerosol instruments. These studies are will represent one of the most comprehensive laboratory observations yet made to study the role of isoprene on nucleation vs. growth of new particles under conditions representative of non-pristine mixed deciduous forests and at a wide range of temperature and relative humidity conditions. This fundamental research is expected to provide new insight into the role of this important biogenic volatile organic compound-isoprene-upon particle formation relevant to cloud condensation and hence climate conditions.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.