Towards a Field-Portable Real-Time Organic and Elemental Carbon Monitor

Parks, David; Raj, K. Vivek; Berry, C. A.; Weakley, Andrew T.; Griffiths, Peter R.; Miller, Art

doi:10.1007/s42461-019-0064-8

Cited by 9 publications

(18 citation statements)

References 14 publications

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“…This suggests that the RONO 2 formation could be an important SOA formation pathway from WB emissions, which, nevertheless, we do not account for quantitatively. A relatively small peak at 1560 cm −1 is also observed in WB aerosols aged by the nitrate radical, which can be attributed to nitroaromatics (Pavia et al, 2008). Weak signatures of aromatics or PAHs are visible at 690-900 cm −1 in the MIR spectra of both primary and aged WB aerosols.…”

Section: Wood Burning -Functional Group Compositionmentioning

confidence: 89%

“…The aged WB samples with high carboxylic acid concentration have a broad OH peak ranging from 2400 to 3400 cm −1 , and their carbonyl absorption frequency is on the lower end of its range (approximately 1708 cm −1 compared to 1715 cm −1 for ketone carbonyl; Fig. 2a) due to the weakening of the C=O bond in dimerized acids (Pavia et al, 2008). Phenol, methoxyphenols, and naphthalene are among the most important SOA precursors, based on their SOA yields, present in wood smoke reported by Bruns et al (2016) and Stefenelli et al (2019).…”

Section: Wood Burning -Functional Group Compositionmentioning

confidence: 99%

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Characterization of primary and aged wood burning and coal combustion organic aerosols in an environmental chamber and its implications for atmospheric aerosols

et al. 2021

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Abstract. Particulate matter (PM) affects visibility, climate, and public health. Organic matter (OM), a uniquely complex portion of PM, can make up more than half of total atmospheric fine PM mass. We investigated the effect of aging on secondary organic aerosol (SOA) concentration and composition for wood burning (WB) and coal combustion (CC) emissions, two major atmospheric OM sources, using mid-infrared (MIR) spectroscopy and aerosol mass spectrometry (AMS). For this purpose, primary emissions were injected into an environmental chamber and aged using hydroxyl (diurnal aging) and nitrate (nocturnal aging) radicals to reach an atmospherically relevant oxidative age. A time-of-flight AMS instrument was used to measure the high-time-resolution composition of non-refractory fine PM, while fine PM was collected on PTFE filters before and after aging for MIR analysis. AMS and MIR spectroscopy indicate an approximately 3-fold enhancement of organic aerosol (OA) concentration after aging (not wall-loss corrected). The OM:OC ratios also agree closely between the two methods and increase, on average, from 1.6 before aging to 2 during the course of aging. MIR spectroscopy, which is able to differentiate among oxygenated groups, shows a distinct functional group composition for aged WB (high abundance of carboxylic acids) and CC OA (high abundance of non-acid carbonyls) and detects aromatics and polycyclic aromatic hydrocarbons (PAHs) in emissions of both sources. The MIR spectra of fresh WB and CC aerosols are reminiscent of their parent compounds with differences in specific oxygenated functional groups after aging, consistent with expected oxidation pathways for volatile organic compounds (VOCs) of each emission source. The AMS mass spectra also show variations due to source and aging that are consistent with the MIR functional group (FG) analysis. Finally, a comparison of the MIR spectra of aged chamber WB OA with that of ambient samples affected by residential wood burning and wildfires reveals similarities regarding the high abundance of organics, especially acids, and the visible signatures of lignin and levoglucosan. This finding is beneficial for the source identification of atmospheric aerosols and interpretation of their complex MIR spectra.

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Section: Wood Burning -Functional Group Compositionmentioning

confidence: 89%

Section: Wood Burning -Functional Group Compositionmentioning

confidence: 99%

Characterization of primary and aged wood burning and coal combustion organic aerosols in an environmental chamber and its implications for atmospheric aerosols

et al. 2021

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“…Baseline correction was performed to eliminate contribution of background drift, light scattering by filter membrane and particles, and absorption by carbonaceous material due to electronic transitions (Russo et al, 2014;Parks et al, 2019). For this purpose, we used a smoothing spline method similar to the approach taken by Kuzmiakova et al (2016).…”

Section: Baseline Correctionmentioning

confidence: 99%

Characterization of primary and aged wood burning and coal combustion organic aerosols in environmental chamber and its implications for atmospheric aerosols

Yazdani¹,

Dudani²,

Takahama³

et al. 2020

Preprint

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Abstract. Particulate matter (PM) affects visibility, climate, and public health. Organic matter (OM), a uniquely complex portion of PM, can make up more than half of total atmospheric fine PM. We investigated the effect of aging on secondary organic aerosol (SOA) concentration and composition for wood burning (WB) and coal combustion (CC) emissions, two major atmospheric OM sources, using mid-infrared (MIR) spectroscopy and aerosol mass spectrometry (AMS). For this purpose, primary aerosols were injected into an environmental chamber and aged using hydroxyl (diurnal aging) and nitrate (nocturnal aging) radicals to reach an atmospherically-relevant oxidative age. A time-of-flight AMS instrument was used to measure high-time-resolution composition of non-refractory fine PM, while fine PM was collected on PTFE filters before and after aging for MIR analysis. AMS and MIR spectroscopy indicate an approximately three-fold enhancement of organic aerosol (OA) concentration after aging (not wall-loss corrected). The OM : OC ratios also agree closely between the two methods and increase, on average, from 1.6, before aging, to 2, during the course of aging. MIR spectroscopy, which is able to differentiate among oxygenated groups, shows a distinct functional group composition for aged WB (high abundance of carboxylic acids) and CC OA (high abundance of non-acid carbonyls) and detects aromatics and polycyclic aromatic hydrocarbons (PAHs) in emissions of both sources. The MIR spectra of fresh WB and CC aerosols are reminiscent of their parent compounds with differences in specific oxygenated functional groups after aging, consistent with expected oxidation pathways for volatile organic compounds (VOCs) of each emission source. The AMS mass spectra also show variations with source and aging that are consistent the MIR functional group (FG) analysis. Finally, comparison of the MIR spectra of chamber WB OA with that of ambient samples affected by residential wood burning and wildfires reveals similarities regarding the high abundance of organics, especially acids, and visible signatures of lignin and levoglucosan. This finding is beneficial to source identification of atmospheric aerosols and interpretation of their complex MIR spectra.

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“…The baseline arises from light scattering by the filter membrane (Mcclenny et al, 1985) and particle as well as electronic transitions of some carbonaceous materials (Russo et al, 2014;Parks et al, 2019). For baseline removal, we used the smoothing spline method on 1500-4000 cm −1 region, where PTFE filter does not absorb, with parameter selection criteria similar to the approach taken by Kuzmiakova et al (2016).…”

Section: Baseline Correction and Normalizationmentioning

confidence: 99%

Estimating mean molecular weight, carbon number, and OM/OC with mid-infrared spectroscopy in organic particulate matter samples from a monitoring network

Yazdani¹,

Dillner²,

Takahama³

2020

Preprint

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Abstract. Organic matter (OM) is a major constituent of fine particulate matter which contributes significantly to degradation of visibility, radiative forcing, and causes adverse health effects. However, due to its sheer compositional complexity, OM is difficult to characterize in its entirety. Mid-infrared spectroscopy has previously proven useful in the study of OM by providing extensive information about functional group composition with high mass recovery. Herein, we introduce a new method for obtaining additional characteristics such as mean carbon number and molecular weight of these complex organic mixtures using the aliphatic C–H absorbance profile in mid-infrared spectrum. We apply this technique to spectra acquired non-destructively from Teflon filters used for fine particulate matter quantification at selected sites of Inter-agency Monitoring of PROtected Visual Environments (IMPROVE) network. Since carbon number and molecular weight are important characteristics used by recent models to describe evolution in OM composition, this technique can provide semi-quantitative, observational constraints of these variables at the scale of the network. For this task, multivariate statistical models are trained on calibration spectra prepared from atmospherically relevant laboratory standards and are applied to ambient samples. Then, the physical basis linking the absorbance profile of this relatively narrow region in the mid-infrared spectrum to the molecular structure is investigated using a classification approach. The multivariate statistical models predict mean carbon number and molecular weight that are consistent with previous values of organic-mass-to-organic-carbon (OM/OC) ratios estimated for the network using different approaches. The results are also consistent with temporal and spatial variations in these quantities associated with aging processes, and different source classes (anthropogenic, biogenic, and burning sources). For instance, the models estimate higher mean carbon number for urban samples and smaller, more fragmented molecules for samples in which substantial aging is anticipated.

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Towards a Field-Portable Real-Time Organic and Elemental Carbon Monitor

Cited by 9 publications

References 14 publications

Characterization of primary and aged wood burning and coal combustion organic aerosols in an environmental chamber and its implications for atmospheric aerosols

Characterization of primary and aged wood burning and coal combustion organic aerosols in an environmental chamber and its implications for atmospheric aerosols

Characterization of primary and aged wood burning and coal combustion organic aerosols in environmental chamber and its implications for atmospheric aerosols

Estimating mean molecular weight, carbon number, and OM/OC with mid-infrared spectroscopy in organic particulate matter samples from a monitoring network

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