Atmospheric photooxidation of alkylbenzenes—I. Carbonyl product analyses

Wang, Yuchen; Jeffries, Harvey E.; Sexton, Kenneth G.

doi:10.1016/s1352-2310(97)00011-3

Cited by 171 publications

(169 citation statements)

References 33 publications

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“…It is possible that C 2 H 2 O results from the oligomerization chemistry of glycolaldehyde (C 2 H 4 O 2 ), which can react by an aldol condensation mechanism with compounds containing a carbonyl group (Scheme 1). Glycolaldehyde has been observed previously in the oxidation of toluene (White et al, 2014;Yu et al, 1997), likely as an oxidation product of methylglyoxal. The mass difference corresponding to H 2 O was not amongst the most common; however, it became more probable in the high-RH sample, consistent with hydration reactions.…”

Section: Positive Ion Modementioning

confidence: 59%

Effect of relative humidity on the composition of secondary organic aerosol from the oxidation of toluene

et al. 2018

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Abstract. The effect of relative humidity (RH) on the chemical composition of secondary organic aerosol (SOA) formed from low-NO x toluene oxidation in the absence of seed particles was investigated. SOA samples were prepared in an aerosol smog chamber at < 2 % RH and 75 % RH, collected on Teflon filters, and analyzed with nanospray desorption electrospray ionization high-resolution mass spectrometry (nano-DESI-HRMS). Measurements revealed a significant reduction in the fraction of oligomers present in the SOA generated at 75 % RH compared to SOA generated under dry conditions. In a separate set of experiments, the particle mass concentrations were measured with a scanning mobility particle sizer (SMPS) at RHs ranging from < 2 to 90 %. It was found that the particle mass loading decreased by nearly an order of magnitude when RH increased from < 2 to 75-90 % for low-NO x toluene SOA. The volatility distributions of the SOA compounds, estimated from the distribution of molecular formulas using the "molecular corridor" approach, confirmed that low-NO x toluene SOA became more volatile on average under high-RH conditions. In contrast, the effect of RH on SOA mass loading was found to be much smaller for high-NO x toluene SOA. The observed increase in the oligomer fraction and particle mass loading under dry conditions were attributed to the enhancement of condensation reactions, which produce water and oligomers from smaller compounds in low-NO x toluene SOA. The reduction in the fraction of oligomeric compounds under humid conditions is predicted to partly counteract the previously observed enhancement in the toluene SOA yield driven by the aerosol liquid water chemistry in deliquesced inorganic seed particles.

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Section: Positive Ion Modementioning

confidence: 59%

Effect of relative humidity on the composition of secondary organic aerosol from the oxidation of toluene

et al. 2018

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“…Comparison of two chemical mechanisms for use in EKMA to calculate hydrocarbon control requirements [101] Carbonyl products in biogenic and aromatic smog systems 1995 Identifying airborne carbonyl compounds in isoprene atmospheric photooxidation products by their PFBHA oximes using gas chromatography/ion trap mass spectrometry [102] 1998 Analysis of airborne carboxylic acids and phenols as their pentafluorobenzyl derivatives: gas chromatography/ion trap mass spectrometry with a novel chemical ionization reagent, PFBOH [103] 1997 Atmospheric photooxidation of alkylbenzenes -I. Carbonyl product analyses [104] 1997 Atmospheric photooxidation of alkylbenzene -II. Evidence of formation of epoxide intermediates [105] 1999 Atmospheric photochemical degradation of 1,4-unsaturated dicarbonyls [106] 1999 Hydroxyl radical and ozone initiated photochemical reactions of 1,3-butadiene [107] 100 and 300 were shared with Whitten and with Dr William Carter at UC-Riverside.…”

Section: Experiments To Test Photochemical Modelsmentioning

confidence: 99%

Early history and rationale for outdoor chamber work at the University of North Carolina

2013

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Environmental context. Imagine in 1968 having to tell the largest cities in the US that they would have to spend billions of dollars to reduce human exposure to a gas in their air that no one emitted and that no one knew for sure how it came to be there. This history recalls how scientists and policy makers met this challenge so that by 1985 effective programs were in place.Abstract. The University of North Carolina (UNC) outdoor chamber facility was established in 1972. The chamber produces reliable and interpretable results using ambient sunlight, temperature and weather, providing an effective physical model system for learning about atmospheric chemistry. This article recounts the 40-year history of the chamber facility, from the early days in understanding ozone-precursor relationship to the latest in studying gas and particulate toxicities on human lung cells. PrefaceLike other models, histories are subject to generalisations, distortions and deletions depending upon who is creating the history. We are sure that this history suffers from these operations. Please forgive us in advance if our recollections and mental constructs are somewhat at odds with your own. Perhaps we can have a 'conversation' about this sometime.

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“…In this study, selective ion analysis for carbonyl-containing compounds was performed with o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine chloride (PFBHA) as described before (Ebersviller et al, 2012a). Mixtures of gases and particles were sampled with midget impinger apparatuses similar to those described before (Yu et al, 1995(Yu et al, , 1997Liu et al, 1999b,a). While we could visually see that some PM was collected in the impinger, we acknowledge that the impingers' collection efficiencies are difficult to accurately quantify for PM.…”

Section: Species-specific Analysis Of Carbonylsmentioning

confidence: 99%

“…The reason that PFBHA-derivative samples are collected directly below the chamber (and not in the laboratory) is that polar compounds can be lost in sample lines. Moreover, direct analysis of carbonyl-compounds by GCMS can be unreliable, while numerous studies have used PFBHA to great effect (Ebersviller et al, 2012a;Seaman et al, 2006;Liu et al, 2005Liu et al, , 1999aYu et al, 1997).…”

Section: Creation and Consistency Of Urban-like Atmospheresmentioning

confidence: 99%

Gaseous VOCs rapidly modify particulate matter and its biological effects – Part 2: Complex urban VOCs and model PM

et al. 2012

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Abstract. This is the second study in a three-part study designed to demonstrate dynamic entanglements among gaseous organic compounds (VOCs), particulate matter (PM), and their subsequent potential biological effects. We study these entanglements in increasingly complex VOC and PM mixtures in urban-like conditions in a large outdoor chamber, both in the dark and in sunlight. To the traditional chemical and physical characterizations of gas and PM, we added new measurements of gas-only-and PM-onlybiological effects, using cultured human lung cells as model living receptors. These biological effects are assessed here as increases in cellular damage or expressed irritation (i.e., cellular toxic effects) from cells exposed to chamber air relative to cells exposed to clean air. Our exposure systems permit side-by-side, gas-only-and PM-only-exposures from the same air stream containing both gases and PM in equilibria, i.e., there are no extractive operations prior to cell exposure for either gases or PM.In Part 1 (Ebersviller et al., 2012a), we demonstrated the existence of PM "effect modification" (NAS, 2004) for the case of a single gas-phase toxicant and an inherently nontoxic PM (mineral oil aerosol, MOA). That is, in the presence of the single gas-phase toxicant in the dark, the initially non-toxic PM became toxic to lung cells in the PM-onlybiological exposure system. In this Part 2 study, we used sunlit-reactive systems to create a large variety of gas-phase toxicants from a complex mixture of oxides of nitrogen and 54 VOCs representative of those measured in US city air. In these mostly day-long experiments, we have designated the period in the dark just after injection (but before sunrise) as the "Fresh" condition and the period in the dark after sunset as the "Aged" condition. These two conditions were used to expose cells and to collect chemical characterization samples. We used the same inherently non-toxic PM from the Part 1 study as the target PM for "effect modification". Fortunately, in the absence of "seed particles", the complex highly-reactive VOC system used does not create any secondary aerosol in situ. All PM present in these tests were, therefore, introduced by injection of MOA to serve as PM-to-be-modified by the gaseous environment. PM addition was only done during dark periods, either before or after the daylight period. The purpose of this design is to test if a non-toxic PM becomes toxic in initially unreacted ("Fresh"), or in reacted ("Aged") complex VOC conditions. To have a complete design, we also tested the effects of clean air and the same VOC conditions, but without introducing any PM. Thus, there were six exposure treatment conditions that were evaluated with the side-by-side, gas-only-and PMonly-effects exposure systems; five separate chamber experiments were performed: two with clean air and three with the complex VOC/NO x mixture.For all of these experiments and exposures, chemical composition data and matching biological effects results for two end-points were compared. Chemic...

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Atmospheric photooxidation of alkylbenzenes—I. Carbonyl product analyses

Cited by 171 publications

References 33 publications

Effect of relative humidity on the composition of secondary organic aerosol from the oxidation of toluene

Effect of relative humidity on the composition of secondary organic aerosol from the oxidation of toluene

Early history and rationale for outdoor chamber work at the University of North Carolina

Gaseous VOCs rapidly modify particulate matter and its biological effects – Part 2: Complex urban VOCs and model PM

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