Composition of Organic Portion of Atmospheric Aerosols in the Los Angeles Area

Mader, P. P.; MacPhee, Robert D.; Lofberg, Robert T.; Larson, Gordon P.

doi:10.1021/ie50510a047

Cited by 41 publications

(11 citation statements)

References 2 publications

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“…As previously indicated, Mader 27 reported heavy aerosol development upon irradiating gasoline in an 8-ft 3 chamber for 30 minutes. He used sunlight and about 100 ppm gasoline containing 25 percent unsaturates in the presence of about five ppm NO 2 .…”

Section: Formation Of Aerosols Without Sulfur Dioxidementioning

confidence: 62%

Studies on the Role of Sulfur Dioxide in Visibility Reduction

Harkins¹,

Nicksic²

1965

Journal of the Air Pollution Control Association

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Section: Formation Of Aerosols Without Sulfur Dioxidementioning

confidence: 62%

Studies on the Role of Sulfur Dioxide in Visibility Reduction

Harkins¹,

Nicksic²

1965

Journal of the Air Pollution Control Association

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“…Some of the earliest work in studying organic aerosol composition in Los Angeles smog and synthetic smog generated in the laboratory was studied using infrared spectroscopy (Mader et al, 1952), and this tool is often used qualitatively for identifying organic aerosol constituents and monitoring changes induced under controlled laboratory conditions (e.g., Hung et al, 2005;Presto et al, 2005;Fu et al, 2013;Kidd et al, 2014;Chen et al, 2016;Yu et al, 2017). The FG analysis approach to quantification of organic matter (OM) was pioneered by Allen and co-workers (Palen et al, 1992;Allen et al, 1994) and further extended by other researchers (Blando et al, 1998;Maria et al, 2002;Coury and Dillner, 2008;Russo et al, 2014). This method typically requires two steps: (1) estimating molar abundances of individual bond types from measured absorbances, and (2) relating bond abundances to FG and carbon content such that the OM mass can be obtained from their summation (Russell, 2003).…”

Section: Introductionmentioning

confidence: 99%

Analysis of functional groups in atmospheric aerosols by infrared spectroscopy: systematic intercomparison of calibration methods for US measurement network samples

2019

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Abstract. Peak fitting (PF) and partial least squares (PLS) regression have been independently developed for estimation of functional groups (FGs) from Fourier transform infrared (FTIR) spectra of ambient aerosol collected on Teflon filters. PF is a model that quantifies the functional group composition of the ambient samples by fitting individual Gaussian line shapes to the aerosol spectra. PLS is a data-driven, statistical model calibrated to laboratory standards of relevant compounds and then extrapolated to ambient spectra. In this work, we compare the FG quantification using the most widely used implementations of PF and PLS, including their model parameters, and also perform a comparison when the underlying laboratory standards and spectral processing are harmonized. We evaluate the quantification of organic FGs (alcohol COH, carboxylic COOH, alkane CH, carbonyl CO) and ammonium, using external measurements (organic carbon (OC) measured by thermal optical reflectance (TOR) and ammonium by balance of sulfate and nitrate measured by ion chromatography). We evaluate our predictions using 794 samples collected in the Interagency Monitoring of PROtected Visual Environments (IMPROVE) network (USA) in 2011 and 238 laboratory standards from Ruthenburg et al. (2014) (available at https://doi.org/10.1016/j.atmosenv.2013.12.034). Each model shows different biases. Overall, estimates of OC by FTIR show high correlation with TOR OC. However, PLS applied to unprocessed (raw spectra) appears to underpredict oxygenated functional groups in rural samples, while other models appear to underestimate aliphatic CH bonds and OC in urban samples. It is possible to adjust model parameters (absorption coefficients for PF and number of latent variables for PLS) within limits consistent with calibration data to reduce these biases, but this analysis reveals that further progress in parameter selection is required. In addition, we find that the influence of scattering and anomalous transmittance of infrared in coarse particle samples can lead to predictions of OC by FTIR which are inconsistent with TOR OC. We also find through several means that most of the quantified carbonyl is likely associated with carboxylic groups rather than ketones or esters. In evaluating state-of-the-art methods for FG abundance by FTIR, we suggest directions for future research.

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“…One of the more dramatic 20th Century achievements in characterizing atmospheric aerosol chemistry addresses the organic fraction (e.g., Mader et al 1952;Jacobson et al 2000). The presence of organic species in aerosols was recognized some time ago, but most of the effort to specify this fraction relied on bulk solvent soluble extracts (e.g., NASN 1965).…”

Section: Mass Concentration and Particle Compositionmentioning

confidence: 99%

Atmospheric Aerosols: Some Highlights and Highlighters, 1950 to 2018

Hidy¹

2019

Aerosol Sci Eng

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The science of atmospheric aerosols began more than a century ago; it has experienced major advancements after the mid-twentieth century with motivation from diverse public interests and concerns for environmental protection. At least six generations of mentored investigators have involvement in these advancements. Since the 1950s, important knowledge has emerged in the theory of the dynamics of suspended particles and advanced measurements. Important developments in the theory of atmospheric aerosols include: (a) nucleation and growth mechanisms, (b) formalization of particle dynamics in the Knudsen regimes, (c) characterization of the mechanisms for the particle-size distribution, (d) identification of chemical processes for atmospheric particle sources, and (e) model integration of particle physical and chemical processes with meteorological processes. Important advances in measurements have included: (a) semicontinuous determination of particle-size distributions, (b) new methods for sampling and analysis of mass concentration and composition, (c) methods for continuous characterization of aerosol chemical properties, and (d) development of direct sensing techniques using optical properties. Examples of breakthroughs in these areas are given in the text. Illustrations of achievements in each of the areas are included in the paper. The survey is completed with comments on the generational nature of investigator contributions to aerosol science.

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Composition of Organic Portion of Atmospheric Aerosols in the Los Angeles Area

Cited by 41 publications

References 2 publications

Studies on the Role of Sulfur Dioxide in Visibility Reduction

Studies on the Role of Sulfur Dioxide in Visibility Reduction

Analysis of functional groups in atmospheric aerosols by infrared spectroscopy: systematic intercomparison of calibration methods for US measurement network samples

Atmospheric Aerosols: Some Highlights and Highlighters, 1950 to 2018

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