Formation of Urban Ultrafine Particles in Houston

该项目重点研究城市大气中可能导致城市超细颗粒形成的大气过程。了解超细颗粒的形成非常重要，因为它们在肺部具有更高的渗透和沉积效率，并且比大颗粒具有更高的毒性。它们还能促进云凝结核的产生。这项研究有助于更好地理解气候和空气质量问题，特别是在城市地区。计划进行两次为期6周的实地活动，用一套最先进的气溶胶和化学仪器测量化学前体，如高氧分子、颗粒大小和化学成分。由于该地区炼油厂、发电厂、船舶航道、城市和海洋排放的气溶胶和气相前体的排放多种多样，因此实地工作将在休斯敦大都会地区进行。需要解决的主要科学问题是：(1)交通排放与新颗粒形成对休斯顿城市超细颗粒的相对贡献是什么？(2)不同温度和NOx （NO+N02）条件下城市高氧有机分子（HOMs）的分子组成是什么？(3)休斯敦不同的化学前体，如硫酸、氨、胺和HOMs，如何促进城市新颗粒的形成？这项研究将支持两名女教师和几名研究生。该奖项反映了美国国家科学基金会的法定使命，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。

This project focuses on atmospheric processes that can lead to the formation of urban ultrafine particles in the urban atmosphere. Understanding the formation of ultrafine particles is important because they have higher penetration and deposition efficiencies in the lung and have higher toxicity than larger particles. They can also enhance the production of cloud condensation nuclei. This research is relevant for better understanding climate and air quality issues, particularly in urban areas.Two 6-week field campaigns are planned for measuring chemical precursors such as highly oxygenated molecules, and particle sizes and chemical composition with a suite of state-of-the-art aerosol and chemical instrumentation. The field work will be conducted in the metropolitan Houston area due to the variety of emissions for aerosol and gas-phase precursors from oil refineries, power plants, ship channels, urban and marine emissions in the region. The main scientific questions to be addressed are: (1) What is the relative contribution of traffic emissions vs. new particle formation to the urban ultrafine particles in Houston? (2) What is the molecular composition of urban HOMs (highly oxygenated organic molecules) under different temperatures and NOx (NO+N02) conditions? (3) How is urban new particle formation facilitated by different chemical precursors, such as sulfuric acid, ammonia, amines, and HOMs in Houston? This research will support two female faculty members and several graduate students.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.