Sensitivities of sulfate aerosol formation and oxidation pathways on the chemical mechanism employed in simulations

Stein, Ariel; Saylor, Rick

doi:10.5194/acp-12-8567-2012

Cited by 23 publications

(13 citation statements)

References 20 publications

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“…Sulfate predicted to be formed by aqueous‐phase oxidation by methyl hydrogen peroxide (MHP) and peroxyacetic acid (PAA) is also predicted to be negligible. However, Stein and Saylor [] show that the relative contributions of sulfate formation pathways depend critically on the chemical mechanism used. Specifically, during the ICARTT 2004 campaign, up to 30% of the sulfate in certain locations is attributable to the aqueous‐phase oxidation of MHP when using CMAQv4.6 with the CBIV mechanism, and very little sulfate is attributable to PAA oxidation.…”

Section: Resultsmentioning

confidence: 99%

Inorganic and black carbon aerosols in the Los Angeles Basin during CalNex

et al. 2013

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[1] We evaluate predictions from the Community Multiscale Air Quality (CMAQ version 4.7.1) model against a suite of airborne and ground-based meteorological measurements, gas-and aerosol-phase inorganic measurements, and black carbon (BC) measurements over Southern California during the CalNex field campaign in May/June 2010. Groundbased measurements are from the CalNex Pasadena ground site, and airborne measurements took place onboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Navy Twin Otter and the NOAA WP-3D aircraft. BC predictions are in general agreement with observations at the Pasadena ground site and onboard the WP-3D, but are consistently overpredicted when compared to Twin Otter measurements. Adjustments to predicted inorganic mass concentrations, based on predicted aerosol size distributions and the AMS transmission efficiency, are shown to be significant. Owing to recent shipping emission reductions, the dominant source of sulfate in the L.A. Basin may now be long-range transport. Sensitivity studies suggest that severely underestimated ammonia emissions, and not the exclusion of crustal species (Ca 2 + , K + , and Mg 2 + ), are the single largest contributor to measurement/model disagreement in the eastern part of the L.A. Basin. Despite overstated NO x emissions, total nitrate concentrations are underpredicted, which suggests a missing source of HNO 3 and/or overprediction of deposition rates. Adding gas-phase NH 3 measurements and size-resolved measurements, up to 10 mm, of nitrate and various cations (e.g. Na + , Ca 2 + , K + ) to routine monitoring stations in the L.A. Basin would greatly facilitate interpreting day-to-day fluctuations in fine and coarse inorganic aerosol.

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Section: Resultsmentioning

confidence: 99%

Inorganic and black carbon aerosols in the Los Angeles Basin during CalNex

et al. 2013

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“…They serve as temporary reservoirs for HO x radicals, contributing to the atmospheric oxidation capacity (Reeves and Penkett, 2003). Peroxides also participate in the conversion of S(IV) to S(VI) in the aqueous phase, leading to the acid precipitation and the formation of secondary sulfate (SO 2− 4 ) aerosols in the troposphere (Calvert et al, 1985;Stein and Saylor, 2012). Furthermore, atmospheric peroxides are considered as the key components of secondary organic aerosol (SOA), which play a significant role in the formation and duration of haze pollution (Kroll and Seinfeld, 2008;Ziemann and Atkinson, 2012;.…”

Section: Introductionmentioning

confidence: 99%

Observation of atmospheric peroxides during Wangdu Campaign 2014 at a rural site in the North China Plain

Wang

Chen

et al. 2016

Atmos. Chem. Phys.

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Abstract. Measurements of atmospheric peroxides were made during Wangdu Campaign 2014 at Wangdu, a rural site in the North China Plain (NCP) in summer 2014. The predominant peroxides were detected to be hydrogen peroxide (H 2 O 2 ), methyl hydroperoxide (MHP) and peroxyacetic acid (PAA). The observed H 2 O 2 reached up to 11.3 ppbv, which was the highest value compared with previous observations in China at summer time. A box model simulation based on the Master Chemical Mechanism and constrained by the simultaneous observations of physical parameters and chemical species was performed to explore the chemical budget of atmospheric peroxides. Photochemical oxidation of alkenes was found to be the major secondary formation pathway of atmospheric peroxides, while contributions from alkanes and aromatics were of minor importance. The comparison of modeled and measured peroxide concentrations revealed an underestimation during biomass burning events and an overestimation on haze days, which were ascribed to the direct production of peroxides from biomass burning and the heterogeneous uptake of peroxides by aerosols, respectively. The strengths of the primary emissions from biomass burning were on the same order of the known secondary production rates of atmospheric peroxides during the biomass burning events. The heterogeneous process on aerosol particles was suggested to be the predominant sink for atmospheric peroxides. The atmospheric lifetime of peroxides on haze days in summer in the NCP was about 2-3 h, which is in good agreement with the laboratory studies. Further comprehensive investigations are necessary to better understand the impact of biomass burning and heterogeneous uptake on the concentration of peroxides in the atmosphere.

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“…Peroxide compounds, including hydrogen peroxide (H 2 O 2 ) and organic peroxides, play an important role in the chemistry of the atmosphere, because they serve as oxidants for the conversion of S(IV) to S(VI) in the atmospheric aqueous phase, resulting in the formation of sulfate aerosol (Calvert et al, 1985;Lind et al, 1987;Stein and Saylor, 2012). Peroxide species also serve as a reservoir for HO x (OH and HO 2 ) radicals (Wallington and Japar, 1990;Vaghjiani and Ravishankara, 1990;Atkinson et al, 1992;Ravetta et al, 2001) and RO x (RO and RO 2 ) radicals (Lightfoot et al, 1991;Reeves and Penkett, 2003).…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous reaction of peroxyacetic acid and hydrogen peroxide on ambient aerosol particles under dry and humid conditions: kinetics, mechanism and implications

Huang

Liang

et al. 2015

Atmos. Chem. Phys.

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Abstract.Hydrogen peroxide (H 2 O 2 ) and organic peroxides play important roles in the cycle of oxidants and the formation of secondary aerosols in the atmosphere. Recent field observations have suggested that the budget of peroxyacetic acid (PAA, CH 3 C(O)OOH) is potentially related to the aerosol phase processes, especially to secondary aerosol formation. Here, we present the first laboratory measurements of the uptake coefficient of gaseous PAA and H 2 O 2 onto ambient fine particulate matter (PM 2.5 ) as a function of relative humidity (RH) at 298 K. The results show that the PM 2.5 , which was collected in an urban area, can take up PAA and H 2 O 2 at the uptake coefficient (γ ) of 10 −4 , and both γ PAA and γ H 2 O 2 increase with increasing RH. The value of γ PAA at 90 % RH is 5.4 ± 1.9 times that at 3 % RH, whereas γ H 2 O 2 at 90 % RH is 2.4 ± 0.5 times that at 3 % RH, which suggests that PAA is more sensitive to the RH variation than H 2 O 2 is. Considering the larger Henry's law constant of H 2 O 2 than that of PAA, the smaller RH sensitivity of the H 2 O 2 uptake coefficient suggests that the enhanced uptake of peroxide compounds on PM 2.5 under humid conditions is dominated by chemical processes rather than dissolution. Considering that mineral dust is one of the main components of PM 2.5 in Beijing, we also determined the uptake coefficients of gaseous PAA and H 2 O 2 on authentic Asian Dust storm (ADS) and Arizona Test Dust (ATD) particles. Compared to ambient PM 2.5 , ADS shows a similar γ value and RH dependence in its uptake coefficient for PAA and H 2 O 2 , while ATD gives a negative dependence on RH. The present study indicates that, in addition to the mineral dust in PM 2.5 , other components (e.g., soluble inorganic salts) are also important to the uptake of peroxide compounds. When the heterogeneous reaction of PAA on PM 2.5 is considered, its atmospheric lifetime is estimated to be 3.0 h on haze days and 7.1 h on non-haze days, values that are in good agreement with the field observations.

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Sensitivities of sulfate aerosol formation and oxidation pathways on the chemical mechanism employed in simulations

Cited by 23 publications

References 20 publications

Inorganic and black carbon aerosols in the Los Angeles Basin during CalNex

Inorganic and black carbon aerosols in the Los Angeles Basin during CalNex

Observation of atmospheric peroxides during Wangdu Campaign 2014 at a rural site in the North China Plain

Heterogeneous reaction of peroxyacetic acid and hydrogen peroxide on ambient aerosol particles under dry and humid conditions: kinetics, mechanism and implications

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