Automated single-ion peak fitting as an efficient approach for analyzing complex chromatographic data.

Chromatography provides important detail on the composition of environmental samples and their chemical processing. However, the complexity of these samples and their tendency to contain many structurally and chemically similar compounds frequently results in convoluted or poorly resolved data. Data reduction from raw chromatograms of complex environmental data into integrated peak areas consequently often requires substantial operator interaction.

Aerosol chemical composition in cloud events by high resolution time-of-flight aerosol mass spectrometry.

This study presents results of direct observations of aerosol chemical composition in clouds. A high-resolution time-of-flight aerosol mass spectrometer was used to make measurements of cloud interstitial particles (INT) and mixed cloud interstitial and droplet residual particles (TOT). The differences between these two are the cloud droplet residuals (RES).

Evolution of organic aerosols in the atmosphere.

Organic aerosol (OA) particles affect climate forcing and human health, but their sources and evolution remain poorly characterized. We present a unifying model framework describing the atmospheric evolution of OA that is constrained by high-time-resolution measurements of its composition, volatility, and oxidation state. OA and OA precursor gases evolve by becoming increasingly oxidized, less volatile, and more hygroscopic, leading to the formation of oxygenated organic aerosol (OOA), with concentrations comparable to those of sulfate aerosol throughout the Northern Hemisphere.

O/C and OM/OC ratios of primary, secondary, and ambient organic aerosols with high-resolution time-of-flight aerosol mass spectrometry.

A recently developed method to rapidly quantify the elemental composition of bulk organic aerosols (OA) using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) is improved and applied to ambient measurements. Atomic oxygen-to-carbon (O/C) ratios characterize the oxidation state of OA, and O/C from ambient urban OA ranges from 0.2 to 0.

Fossil-fueled power plants as a source of atmospheric carbon monoxide.

Elevated carbon monoxide (CO) mixing ratios in excess of those derived from emissions inventories have been observed in plumes from one gas- and coal-fired power plant and three of four lignite coal-fired electric utility power plants observed in east and central Texas. Observations of elevated CO on days characterized by differing wind directions show that CO emissions from the lignite plants were relatively constant over time and cannot be ascribed to separate sources adjacent to the power plants. These three plants were found to be emitting CO at rates 22 to 34 times those tabulated in State and Federal emissions inventories.