| The Nano Aerosol Mass Spectrometer (NAMS) is a single particle mass spectrometer capable of obtaining highly time-resolved mass spectral data for 10-30nm particles. Understanding of the composition of nanoparticles in this size range is crucial for developing theories about how particles grow from gas-phase precursors to a size (∼50nm) where they can have large impacts on climate.;This thesis will discuss the NAMS in detail and focus on development of a second-generation improvement. Improvement of performance will be accomplished by first looking at each component in detail and determining: 1) if there are any sources of particle loss and 2) if there is a method of reducing this particle loss. These steps are accomplished using a combination of simulated (SIMION) and experimental results. The portions of the instrument that are examined inlcude the aerodynamic lens, the particle digital guide, the field adjusting lens (FAL), the digital trap, the laser/laser plume and the time-of-flight (TOF). After sources of particle loss are characterized, maximizing the instrumental performance is accomplished using either the original or an improved design. Three new instrumental changes and their improved particle detection are quantified using a combination of laboratory and ambient measurements.;The NAMS was deployed on 2 field campaigns: Pasadena, California and Hyytiälä, Finland. These results provide substantial insight into nanoparticle formation and quantitative particle composition in urban and rural environment. The data collected on the campaigns are compared with data collected by other particle mass spectrometers. At the California site, particle formation was observed in the early afternoon and was attributed to atmospheric processing of gas and particle phase species that originated from the downtown, Los Angeles area during morning rush hour. The Finnish site showed different particles events which were characterized as new particle formation at or near the collection site. These particles likely formed when clean air masses from the northwest encountered biogenic precursors and increased ozone/sulfuric acid levels. It was observed that particulate sulfate increased from 20-50% on event and the O/C of the organic ratio decreased, signifying primarily sulfate and freshly formed organic matter being present during these formation events. |
