Development of an Integrated System for Analyses of Aerosol Composition and Chemistry

主要研究仪器（MRI）的建议是开发一个全面的实验室系统，以表征气溶胶的成分和化学。三个分析子系统将被组装并集成到一个独特而强大的系统中，用于研究被认为在地球大气中很重要的气溶胶颗粒的成分，尺寸分布和反应性。控制尺寸和化学组成的颗粒将用常用的技术如雾化器和流化床雾化器产生。气溶胶的特点是微分迁移率分析仪和空气动力学粒度分析仪，随后注入到一个压力和温度控制的流动系统类似于那些用于研究高活性自由基和弱结合物种。在该反应室中，颗粒将暴露于不同浓度的气体，如硝酸、水蒸气、无机酸和有机化合物。将通过可调谐二极管激光光谱法（TDLS）、化学电离质谱法（CIMS）和傅里叶变换红外光谱法（FTIR）监测稳定物质（反应物和产物）的气相组成。将通过光学散射技术原位监测颗粒数量和尺寸分布。最后，颗粒将通过空气动力学入口聚集到真空室中，在真空室中，它们将通过气溶胶飞行时间确定大小，并通过质谱法确定其组成。 该项目的长期目标是建立一个多学科的气溶胶科学中心，促进大学，国家实验室和工业界研究人员之间的密切合作。

This Major Research Instrumentation (MRI) proposal is to develop a comprehensive laboratory system to characterize the composition and chemistry of aerosols. Three analytical subsystems will be assembled and integrated into a unique and powerful system for studying the composition, size distribution, and reactivity of aerosol particles believed to be important in the earth's atmosphere. Particles of controlled size and chemical composition will be generated with commonly used techniques such an atomizer and a fluidized bed nebulizer. The aerosols will be characterized by differential mobility analyzers and aerodynamic particle sizers and subsequently injected into a pressure- and temperature-controlled flow system similar to those employed for studies of highly reactive radicals and weakly bound species. In this reaction chamber the particles will be exposed to variable concentrations of gases like nitric acid, water vapor, inorganic acids, and organic compounds. The gas-phase composition of stable species (both reactants and products) will be monitored by tunable diode laser spectroscopy (TDLS), chemical ionization mass spectrometry (CIMS), and Fourier transform infrared spectroscopy (FTIR). The particle number and size distributions will be monitored in situ by optical scattering techniques. Finally, the particles will be focused through an aerodynamic inlet into a vacuum chamber where they will be sized by aerosol time-of-flight and their composition determined by mass spectrometry. The long-term goal of this project is to establish a multidisciplinary center for aerosol science which will foster close collaborations between investigators in universities, national laboratories, and industry.