Acidity of size-fractionated aerosol particles

Ludwig, John H.; Klemm, Otto

doi:10.1007/bf00279508

Cited by 33 publications

(15 citation statements)

References 32 publications

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“…As the modeled pH strongly impacts the rate and the intensity of oligomer formation, its robustness was questioned. Although no direct measurements of the pH of the aerosol have been realized yet, our calculations are consistent with previous experimental studies reporting strongly acidic fine particles (Ludwig and Klemm, 1990;Herrmann, 2003;Keene et al, 2004). Our results are also consistent with the work of Xue et al (2011), which is based on chemical composition and meteorological data collected at a suburban site in Hong Kong and which estimated the aerosol pH to range between −1.87 and 3.12.…”

Section: Driving Parameters Of Both Approachessupporting

confidence: 92%

Oligomer formation in the troposphere: from experimental knowledge to 3-D modeling

et al. 2016

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Abstract. The organic fraction of atmospheric aerosols has proven to be a critical element of air quality and climate issues. However, its composition and the aging processes it undergoes remain insufficiently understood. This work builds on laboratory knowledge to simulate the formation of oligomers from biogenic secondary organic aerosol (BSOA) in the troposphere at the continental scale. We compare the results of two different modeling approaches, a first-order kinetic process and a pH-dependent parameterization, both implemented in the CHIMERE air quality model (AQM) (www.lmd.polytechnique.fr/chimere), to simulate the spatial and temporal distribution of oligomerized secondary organic aerosol (SOA) over western Europe. We also included a comparison of organic carbon (OC) concentrations at two EMEP (European Monitoring and Evaluation Programme) stations. Our results show that there is a strong dependence of the results on the selected modeling approach: while the irreversible kinetic process leads to the oligomerization of about 50 % of the total BSOA mass, the pH-dependent approach shows a broader range of impacts, with a strong dependency on environmental parameters (pH and nature of aerosol) and the possibility for the process to be reversible. In parallel, we investigated the sensitivity of each modeling approach to the representation of SOA precursor solubility (Henry's law constant values). Finally, the pros and cons of each approach for the representation of SOA aging are discussed and recommendations are provided to improve current representations of oligomer formation in AQMs.

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Section: Driving Parameters Of Both Approachessupporting

confidence: 92%

Oligomer formation in the troposphere: from experimental knowledge to 3-D modeling

et al. 2016

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“…The three most abundant ions were NO 3 − , contributing 45% (AA) and 43% (FA) to ionic aerosol mass, respectively; NH 4 + (21% and 29%); and SO 4 2− (24% and 10%) (table 1). The aerosol concentration in the AA greenhouse was about half of that in the the atmosphere that caused FDAP in a remote forest site in 1988 (Ludwig and Klemm 1990, (table 1). For gas phase NH 3 and SO 2 , mean AA and FA concentrations differed by less than 10% (table 2(a)); monthly AA and FA concentrations were highly correlated (r 2 > 0.9) and close to the 1:1 line (figures 2 and S3).…”

Section: Plants and Greenhousesmentioning

confidence: 98%

“…Mean ionic aerosol mass concentrations, measured in the AA and FA greenhouses throughout 2015 (see table S1 for concentrations in ppb). FDAP: reported ionic aerosol mass concentrations within a remote area affected by forest decline from air pollution, measured 1988 in northeastern Bavaria, Germany (Ludwig and Klemm 1990, rural site WF, all size classes combined). Ratios for Σ FDAP are calculated without K + .…”

Section: Plants and Greenhousesmentioning

confidence: 99%

Camouflaged as degraded wax: hygroscopic aerosols contribute to leaf desiccation, tree mortality, and forest decline

Burkhardt

Zinsmeister

Grantz

et al. 2018

Environ. Res. Lett.

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Some 40 years ago, air pollution caused widespread forest decline in Central Europe and eastern North America. More recently, high levels of tree mortality worldwide are thought to be driven by rising temperatures and increasing atmospheric drought. A neglected factor, possibly contributing to both phenomena, is the foliar accumulation of hygroscopic aerosols. Recent experiments with experimentally added aerosols revealed that foliar aerosol accumulation can (i) create the microscopic impression of 'wax degradation', considered an important proxy of forest decline associated with air pollution, though the mechanism remains unexplained; and (ii) increase epidermal minimum conductance (g min ), a measure of cuticular permeability and completeness of stomatal closure-both could lead to reduced drought tolerance. Here, those studies with applied aerosol are extended by addressing plant responses to reduction of ambient aerosol.Scots pine, silver fir, and common oak seedlings were grown for 2 years in greenhouses ventilated with ambient air (AA) or air filtered to remove nearly all aerosol particles (FA). Removal of ambient aerosol prevented the development of amorphous structures viewed in the electron microscope that have typically been interpreted as degraded waxes. Lower g min values suggested that FA plants had better stomatal control and therefore greater drought tolerance than AA plants. The co-occurrence of apparent wax degradation and reduced drought tolerance in AA plants suggests a common cause. This may be mediated by the deliquescence and spreading of hygroscopic aerosols across the leaf surface. The liquid film produced may penetrate the stomata and facilitate unproductive stomatal transpiration. In this way, aerosol pollution may enhance the impacts of atmospheric drought, and may damage trees and forests on large spatial scales.

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“…As the parameterization used an effective Henry's law constant, the formation of oligomers could strongly vary with the pH and the amount of water. However, fine particles are generally very acidic [ Ludwig and Klemm , 1990; Keene et al , 2004] and oligomer formation from BiA0D will then in fact appear as an irreversible process, even though the parameterization is formulated as a reversible process.…”

Section: Model Developmentmentioning

confidence: 99%

A hydrophilic/hydrophobic organic (H²O) aerosol model: Development, evaluation and sensitivity analysis

Couvidat¹,

Debry²,

Sartelet³

et al. 2012

J. Geophys. Res.

105

181

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A secondary organic aerosol (SOA) model, the Hydrophilic/Hydrophobic Organic model (H2O), is presented and evaluated over Europe. H2O uses surrogate organic molecules to represent the myriad of SOA species and distinguishes two kinds of surrogate species: hydrophilic species (which condense preferentially into an aqueous phase) and hydrophobic species (which condense only into an organic phase). These surrogate species are formed from the oxidation in the atmosphere of volatile organic compounds. H2O includes several important processes, including the effect of nitrogen oxides (NOX) on SOA formation, the dissociation of organic acids in an aqueous phase, the oligomerization of aldehydes, the non‐ideality of the particle phase and the hygroscopicity of organics. Concentrations of organic aerosols were simulated over Europe from July 2002 to July 2003 for comparison with measurements of the European Monitoring Evaluation Program (EMEP). In H2O, primary organic aerosols (POA) are considered as semi‐volatile organic compounds (SVOC) present in both the gas phase and the particle phase. Taking into account the gas‐phase fraction of SVOC increases significantly organic PM concentrations, particularly in winter, in better agreement with observations. The impacts on organic aerosol formation of ideality, of the choice of the parameterization for isoprene SOA formation, and of the OM/OC ratio of the model were also investigated. Assuming ideality in H2O was found to lead to a small decrease in OM. Compared to a two‐product parameterization, the parameterization of Couvidat and Seigneur [2011] for SOA formation from isoprene oxidation leads to a significant increase in isoprene SOA by taking into account their hydrophilic properties and suggests that most models may currently underestimate isoprene SOA.

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Acidity of size-fractionated aerosol particles

Cited by 33 publications

References 32 publications

Oligomer formation in the troposphere: from experimental knowledge to 3-D modeling

Oligomer formation in the troposphere: from experimental knowledge to 3-D modeling

Camouflaged as degraded wax: hygroscopic aerosols contribute to leaf desiccation, tree mortality, and forest decline

A hydrophilic/hydrophobic organic (H²O) aerosol model: Development, evaluation and sensitivity analysis

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Acidity of size-fractionated aerosol particles

Cited by 33 publications

References 32 publications

Oligomer formation in the troposphere: from experimental knowledge to 3-D modeling

Oligomer formation in the troposphere: from experimental knowledge to 3-D modeling

Camouflaged as degraded wax: hygroscopic aerosols contribute to leaf desiccation, tree mortality, and forest decline

A hydrophilic/hydrophobic organic (H2O) aerosol model: Development, evaluation and sensitivity analysis

Contact Info

Product

Resources

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A hydrophilic/hydrophobic organic (H²O) aerosol model: Development, evaluation and sensitivity analysis