Secondary Organic Aerosol Yields from the Oxidation of Benzyl Alcohol

Charan, Sophia M.; Buenconsejo, Reina S.; Seinfeld, John H.

doi:10.5194/acp-2020-492

Cited by 4 publications

(14 citation statements)

References 37 publications

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“…A limiting factor could be the availability of organic material. Similar trends were observed by Charan et al (2020), with initial surface areas above ∼ 1800 µm 2 cm −3 becoming insignificant for SOA yields (the numerical difference is not surprising considering the fact that the experimental protocol is quite different from that of this study). This could explain why the three points with higher initial [PS] (1 order of magnitude above the preceding ones) have an hourly [PM] increase on the same order of magnitude as the preceding points.…”

Section: Evolution Of Particles From Diesel Exhaustsupporting

confidence: 83%

Evolution under dark conditions of particles from old and modern diesel vehicles in a new environmental chamber characterized with fresh exhaust emissions

et al. 2021

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Abstract. Atmospheric particles have several impacts on health and the environment, especially in urban areas. Parts of those particles are not fresh and have undergone atmospheric chemical and physical processes. Due to a lack of representativeness of experimental conditions and experimental artifacts such as particle wall losses in chambers, there are uncertainties on the effects of physical processes (condensation, nucleation and coagulation) and their role in particle evolution from modern vehicles. This study develops a new method to correct wall losses, accounting for size dependence and experiment-to-experiment variations. It is applied to the evolution of fresh diesel exhaust particles to characterize the physical processes which they undergo. The correction method is based on the black carbon decay and a size-dependent coefficient to correct particle distributions. Six diesel passenger cars, Euro 3 to Euro 6, were driven on a chassis dynamometer with Artemis Urban cold start and Artemis Motorway cycles. Exhaust was injected in an 8 m3 chamber with Teflon walls. The physical evolution of particles was characterized during 6 to 10 h. Increase in particle mass is observed even without photochemical reactions due to the presence of intermediate-volatility organic compounds and semi-volatile organic compounds. These compounds were quantified at emission and induce a particle mass increase up to 17 % h−1, mainly for the older vehicles (Euro 3 and Euro 4). Condensation is 4 times faster when the available particle surface is multiplied by 6.5. If initial particle number concentration is below [8–9] × 104 cm−3, a nucleation mode seems to be present but not measured by a scanning mobility particle sizer (SMPS). The growth of nucleation-mode particles results in an increase in measured [PN]. Above this threshold, particle number concentration decreases due to coagulation, up to −27 % h−1. Under those conditions, the chamber and experimental setup are well suited to characterizing and quantifying the process of coagulation.

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Section: Evolution Of Particles From Diesel Exhaustsupporting

confidence: 83%

Evolution under dark conditions of particles from old and modern diesel vehicles in a new environmental chamber characterized with fresh exhaust emissions

et al. 2021

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“…A voltage scan from 15 to 9875 V was performed in 240 s every 330 s. Aerosol from the chamber flowed through an X-ray source to provide a known charge distribution, and the size distributions were determined using the data inversion method described by Mai et al (2018). Experiment C2 required a logarithmic fit to the largest particles present, as described in Charan et al (2020), which is the source of the higher SOA yield uncertainty than in the other experiments (see Table 1). Conversions to mass concentration were performed by assuming that the aerosol density was 1.52 ± 0.04 g cm −3 , which was the density calculated at [OH] ≈ 9.4 × 10 9 molec.…”

Section: Methodsmentioning

confidence: 99%

“…Uncertainty estimates for all the instruments used in this study were determined as described in Charan et al (2020). For the chamber experiments, particlewall-deposition corrections were performed by calculating a diameter-independent first-order exponential fit (β = 1-7 × 10 −4 min −1 ) to the particle volume concentration during the 3 h prior to the onset of oxidation and applying that correction to the rest of the experiment.…”

Section: Methodsmentioning

confidence: 99%

Secondary organic aerosol formation from the oxidation of decamethylcyclopentasiloxane at atmospherically relevant OH concentrations

et al. 2022

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Abstract. Decamethylcyclopentasiloxane (D5, C10H30O5Si5) is measured at parts per trillion (ppt) levels outdoors and parts per billion (ppb) levels indoors. Primarily used in personal care products, its outdoor concentration is correlated to population density. Since understanding the aerosol formation potential of volatile chemical products is critical to understanding particulate matter in urban areas, the secondary organic aerosol yield of D5 was studied under a wide range of OH concentrations and, correspondingly, OH exposures using both batch-mode chamber and continuously run flow tube experiments. These results were comprehensively analyzed and compared to two other secondary organic aerosol (SOA) yield datasets from literature. It was found that the SOA yield from the oxidation of D5 is extremely dependent on either the OH concentration or exposure. For OH concentrations of ≲ 107 molec.cm-3 or OH exposures of ≲ 2 × 1011 molec.scm-3, the SOA yield is largely < 5 % and usually ∼ 1 %. This is significantly lower than SOA yields previously reported. Using a two-product absorptive partitioning model for the upper bound SOA yields, the stoichiometric mass fraction and absorptive partitioning coefficients are, for the first product, α1 = 0.056 and KOM,1 = 0.022 m3 µg−1; for the second product, they are α2 = 7.7 and KOM,2 = 4.3 × 10−5 m3 µg−1. Generally, there are high SOA yields (> 90 %) at OH mixing ratios of 5 × 109 molec.cm-3 or OH exposures above 1012 molec.scm-3.

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“…Few laboratory chamber studies have investigated the oxidation processes of other oxygenated gas-phase species (e.g., Charan et al, 2020;, so few experimental data exist about the SOA yields or oxidation products of oxygenated SOA precursors. Additionally, many models that predict the products of oxidation reactions (e.g., SOM and VBS) have not been parameterized or evaluated using oxygenated precursors.…”

Section: Parameterizing Soa Formation From Vcpsmentioning

confidence: 99%

“…While VCPs do emit some of these species, they also emit many oxygenated compounds (Seltzer et al, 2021;McDonald et al, 2018). The implications of a few important oxygenated precursors for air quality have recently been quantified (e.g., Janechek et al, 2017;Charan et al, 2020;, but many oxygenated precursors have not been studied in a laboratory setting. For the few oxygenated VCPs that have been studied in laboratory chambers, SOA yields were reported under unrealistic atmospheric conditions, e.g., high OH and aerosol seed concentrations (Charan et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Modeling secondary organic aerosol formation from volatile chemical products

et al. 2021

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Abstract. Volatile chemical products (VCPs) are commonly used consumer and industrial items that are an important source of anthropogenic emissions. Organic compounds from VCPs evaporate on atmospherically relevant timescales and include many species that are secondary organic aerosol (SOA) precursors. However, the chemistry leading to SOA, particularly that of intermediate-volatility organic compounds (IVOCs), has not been fully represented in regional-scale models such as the Community Multiscale Air Quality (CMAQ) model, which tend to underpredict SOA concentrations in urban areas. Here we develop a model to represent SOA formation from VCP emissions. The model incorporates a new VCP emissions inventory and employs three new classes of emissions: siloxanes, oxygenated IVOCs, and nonoxygenated IVOCs. VCPs are estimated to produce 1.67 µg m−3 of noontime SOA, doubling the current model predictions and reducing the SOA mass concentration bias from −75 % to −58 % when compared to observations in Los Angeles in 2010. While oxygenated and nonoxygenated intermediate-volatility VCP species are emitted in similar quantities, SOA formation is dominated by the nonoxygenated IVOCs. Formaldehyde and SOA show similar relationships to temperature and bias signatures, indicating common sources and/or chemistry. This work suggests that VCPs contribute up to half of anthropogenic SOA in Los Angeles and models must better represent SOA precursors from VCPs to predict the urban enhancement of SOA.

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Secondary Organic Aerosol Yields from the Oxidation of Benzyl Alcohol

Cited by 4 publications

References 37 publications

Evolution under dark conditions of particles from old and modern diesel vehicles in a new environmental chamber characterized with fresh exhaust emissions

Evolution under dark conditions of particles from old and modern diesel vehicles in a new environmental chamber characterized with fresh exhaust emissions

Secondary organic aerosol formation from the oxidation of decamethylcyclopentasiloxane at atmospherically relevant OH concentrations

Modeling secondary organic aerosol formation from volatile chemical products

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