Learn More
Field measurements of secondary organic aerosol (SOA) find significantly higher mass loads than predicted by models, sparking intense effort focused on finding additional SOA sources but leaving the fundamental assumptions used by models unchallenged. Current air-quality models use absorptive partitioning theory assuming SOA particles are liquid droplets,(More)
While multifunctional organic nitrates are formed during the atmospheric oxidation of volatile organic compounds, relatively little is known about their signatures in particle mass spectrometers. High resolution time-of-flight aerosol mass spectrometry (HR-ToF-AMS) and FTIR spectroscopy on particles impacted on ZnSe windows were applied to NH(4)NO(3),(More)
We have investigated the thermodynamics and kinetics of ammonium nitrate/water and mixed ammonium nitrate/succinic acid/water microparticles. The water activity of ammonium nitrate microparticles is determined as a function of composition down to 12% relative humidity by accounting for the rapid evaporation of ammonia and nitric acid. Both the observed(More)
We describe a system designed to measure the size, composition and density of individual spherical particles in real-time. It uses a Differential Mobility Analyzer (DMA) to select a monodisperse particle population and the single particle mass spectrometer to measure individual particle aerodynamic diameter. Together the mobility and aerodynamic diameters(More)
Though ammonium bisulfate is one of the most common of atmospheric hygroscopic aerosols, knowledge of its interaction with water has, until now, been extremely limited. This paper presents our observations on single isolated ammonium bisulfate aerosol particles, as they interact with water vapor at temperatures ranging from -40 to 30 °C. The complete phase(More)
Formation, properties, transformations, and temporal evolution of secondary organic aerosol (SOA) particles depend strongly on SOA phase. Recent experimental evidence from both our group and several others indicates that, in contrast to common models' assumptions, SOA constituents do not form a low-viscosity, well-mixed solution, yielding instead a(More)
The interaction between atmospheric particles and water vapor impacts directly and significantly the effect that these particles exert on the atmosphere. The hygroscopicity of individual particles, which is a quantitative measure of their response to changes in relative humidity, is related to their internal compositions. To properly include atmospheric(More)
A limitation of the existing ThemeRiver [1] paradigm is that only one attribute can be displayed per theme. In this poster, we present a 3D extension, which enables us to display two attributes of each variable in the data stream. We further describe a technique to construct the Bezier surface that satisfies the ThemeRiver requirements, such as boundedness(More)
Primary organic aerosol (POA) and associated vapors can play an important role in determining the formation and properties of secondary organic aerosol (SOA). If SOA and POA are miscible, POA will significantly enhance SOA formation and some POA vapor will incorporate into SOA particles. When the two are not miscible, condensation of SOA on POA particles(More)
Radiative transfer models consistently overestimate surface diffuse downward irradiance in cloud-free atmospheres by 9 to 40% at two low altitude sites while correctly calculating direct-normal Solar irradiance. For known systematic and random measurement errors and for realistic aerosol optical properties, the discrepancy can be resolved by a reduction in(More)