Chemical characterisation of semi-volatile and aerosol compounds from the photooxidation of toluene and NOx

White, Stephen; Jamie, Ian M.; Angove, Dennys E.

doi:10.1016/j.atmosenv.2013.11.023

Cited by 43 publications

(38 citation statements)

References 39 publications

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“…The oxidation products of toluene can be found in both gaseous and particulate phases, as reported by earlier research (Forstner et al, 1997;Sato et al, 2007;White et al, 2014). Our analysis did not include a detailed chemical analysis of the particulate phase, and therefore the yields in Tables 3 and 4 could be underestimations.…”

Section: Soa Formation Experimentsmentioning

confidence: 69%

Characterization and testing of a new environmental chamber

et al. 2015

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Abstract. A 29 m 3 Teflon chamber, designed for studies on the aging of combustion aerosols, at the University of Eastern Finland is described and characterized. The chamber is part of a research facility, called Ilmari, where small-scale combustion devices, a dynamometer for vehicle exhaust studies, dilution systems, the chamber, and cell and animal exposure devices are located side by side under the same roof. The small surface-to-volume ratio of the chamber enables reasonably long experiment times, with particle wall loss rate constants of 0.088, 0.080, 0.045, and 0.040 h −1 for polydisperse, 50, 100, and 200 nm monodisperse aerosols, respectively. The NO 2 photolysis rate can be adjusted from 0 to 0.62 min −1 . The irradiance spectrum is centered at either 350 or 365 nm, and the maximum irradiance, produced by up to 160 blacklight lamps, is 29.7 W m −2 , which corresponds to the ultraviolet (UV) irradiance in Central Finland at noon on a sunny day in the midsummer. The temperature inside the chamber is uniform and can be kept at 25 ± 1 • C. The chamber is kept in an overpressure with a moving top frame, which reduces sample dilution and entrance of contamination during an experiment. The functionality of the chamber was tested with oxidation experiments of toluene, resulting in secondary organic aerosol (SOA) yields of 12-42 %, depending on the initial conditions, such as NO x concentration and UV irradiation. The highest gaseous oxidation product yields of 12.4-19.5 % and 5.8-19.5 % were detected with ions corresponding to methyl glyoxal (m/z 73.029) and 4-oxo-2-pentenal (m/z 99.044), respectively. Overall, reasonable yields of SOA and gaseous reaction products, comparable to those obtained in other laboratories, were obtained.

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Section: Soa Formation Experimentsmentioning

confidence: 69%

Characterization and testing of a new environmental chamber

et al. 2015

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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: 95%

“…However, this does not rule out the possibility that RH may affect the SOA chemical composition and yield by mechanisms other than those mentioned above. Indeed, White et al (2014) investigated the effect of RH on the composition of toluene SOA produced under high-NO x conditions without seed particles and observed higher toluene SOA yields at elevated RH and higher yields of photooxidation products. In this work, we studied the composition of low-NO x toluene SOA formed under dry and humid conditions in the absence of seed particles.…”

Section: Introductionmentioning

confidence: 99%

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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“…Aromatic hydrocarbons are proved to have a negative effect on human health (Guo et al, 2004). Meanwhile, the atmospheric transformation of aromatic species has attracted numerous attentions due to their potential in ozone production and secondary organic aerosol (SOA) formation (Loza et al, 2012;White et al, 2014). For example, field measurements carried out in Seoul, Korea, proved that xylene is the largest contributor to local ozone formation .…”

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confidence: 99%

Effect of aluminium dust on secondary organic aerosol formation in m-xylene/NO x photo-oxidation

Liu

Chu

et al. 2014

Sci. China Earth Sci.

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As an important anthropogenic volatile organic compound (VOC), m-xylene has attracted numerous attentions due to its potential in secondary organic aerosol (SOA) formation. In this study, effects of aluminium dust seeds (boehmite and alumina) on SOA yield and aerosol size in m-xylene/NO x photo-oxidation were investigated in a 2 m 3 smog chamber at 30°C and 50% relative humidity. Compared to the seed-free system, the presence of aluminium seeds resulted in an increase in the SOA yield, and also enhanced the O 3 concentration in the chamber. The photolysis of O 3 is a major source of OH radical, which is the most important oxidant of m-xylene. The increase in O 3 concentration could result in the generation of more OH radicals, and finally contribute to the SOA formation. Seed particles influence the SOA size mainly by acting as condensation nuclei. Semi-volatile organic compounds (SVOCs) were condensed onto these nuclei, resulting in the increase in SOA size. However, when aluminium seeds with high concentrations were introduced into the system, SVOCs that had been condensed onto each particle were dispersed by these seeds, leading to the reduction in aerosol size.

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Chemical characterisation of semi-volatile and aerosol compounds from the photooxidation of toluene and NOx

Cited by 43 publications

References 39 publications

Characterization and testing of a new environmental chamber

Characterization and testing of a new environmental chamber

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

Effect of aluminium dust on secondary organic aerosol formation in m-xylene/NO x photo-oxidation

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