2004), or probe particular sections of individual particles (time-of-flight secondary ion mass spectrometry, Tervahattu etВ al. 2010 thermal desorption chemical ionization mass spectrometry, Smith etВ al. Some techniques target a particular size fraction (cluster chemical ionization mass spectrometry, Zhao etВ al. 2006 transmission electron microscopy with electron energy-loss spectroscopy, Adachi and Buseck 2008 scanning transmission X-ray microscopy with NEXAFS, Russell 2003) can provide metrics linked to number, mass composition, and morphology, but often not all together, and representativeness is dependent on sampling statistics. Single-particle methods (aerosol time-of-flight mass spectrometry, Noble and Prather 2000 scanning electron microscopy with energy dispersive X-ray, Laskin etВ al. 2007 near-edge X-ray absorption fine structure, Russell 2003 Raman spectroscopy, Chan etВ al. 2003 nuclear magnetic resonance, Decesari etВ al. 2010), or functional bonds through spectroscopy (Fourier transform infrared spectroscopy, Maria etВ al. 2008), atomic composition also through aerosol mass spectrometry (time-of-flight aerosol mass spectrometry Chhabra etВ al.

2004), mass fragments through mass spectrometry (Schauer etВ al. Composition is typically quantified in units of organic carbon (OC) through evolved gas analysis (EGA) (Subramanian etВ al. Each method varies in the amount of organic content (mass concentration) it can quantify, and to what extent individual species can be resolved (chemical specificity). Given the dimensionality and domain size of organic aerosol characteristics (comprising size, shape, quantity, and composition), its representation must be constructed through the combination of analytical techniques that provide complementary information. Measurement of organic aerosol composition and abundance in the atmosphere provide a basis from which we can infer sources, predict potential impacts on health and climate, and provide constraints on representations for mathematical and computational modeling of the atmospheric system for simulating alternative scenarios relevant to adaptation or policy decision-making.

2004) and remains undercharacterized with respect to their quantity and potential impacts on health and climate (Kanakidou etВ al. The number of molecules comprising the organic aerosol fraction is numerous (Hamilton etВ al. The procedure for spectra interpretation and quantitative analysis is described through the context of an algorithm in which contributions of background and analyte absorption to the infrared spectrum are apportioned by the superposition of lineshapes constrained by laboratory measurements.Д¬opyright 2013 American Association for Aerosol ResearchДЄtmospheric aerosols contain some mixture of nitrate, sulfate, ammonium, crustal elements, sea salt, black carbon, and organic molecules (Seinfeld and Pandis 2006). Furthermore, functional group abundances of two aldehydic compounds, 2-deoxy-d-ribose and glyceraldehyde, atomized from aqueous solution are in quantitative agreement with number of bonds predicted after transformation of these compounds into diols. Molar absorptivities for carbonyl and hydroxyl bonds in carboxylic groups are obtained for several dicarboxylic compounds, and applied to a multifunctional compound and mixture to demonstrate the applicability of this method for more complex samples. ( 2009) for apportionment and quantification of oxygenated (carbonyl and hydroxyl) functional groups from infrared absorption spectra. This study describes and evaluates the algorithm introduced by Russell etВ al. 2004), we advance a functional group representation of organic molecules as measured by Fourier transform infrared spectroscopy (FTIR) to characterize the chemical composition of particle samples. As the number of organic molecules in the atmosphere are diverse in number (Hamilton etВ al. Organic aerosols can make up as much as 80% of atmospheric aerosols (Lim and Turpin 2002), and so its quantification and characterization plays an important role in reducing our uncertainty with regards to aerosol impacts on health and climate.

Atmospheric aerosols are one of the least understood components of the climate system and incur adverse health effects on susceptible populations.

Carbonyl functional group