scholarly journals Effects of Precursor Concentration and Acidic Sulfate in Aqueous Glyoxal−OH Radical Oxidation and Implications for Secondary Organic Aerosol

2009 ◽  
Vol 43 (21) ◽  
pp. 8105-8112 ◽  
Author(s):  
Yi Tan ◽  
Mark J. Perri ◽  
Sybil P. Seitzinger ◽  
Barbara J. Turpin
Keyword(s):  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Precursor Concentration ◽  
Oh Radical ◽  
Radical Oxidation ◽  
Acidic Sulfate

scholarly journals Chemical insights, explicit chemistry, and yields of secondary organic aerosol from OH radical oxidation of methylglyoxal and glyoxal in the aqueous phase

2013 ◽  
Vol 13 (17) ◽  
pp. 8651-8667 ◽  
Author(s):  
Y. B. Lim ◽  
Y. Tan ◽  
B. J. Turpin
Keyword(s):  
Acetic Acid ◽  
Aqueous Phase ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Oxidation Products ◽  
Radical Reactions ◽  
Organic Radical ◽  
Oh Radical ◽  
Radical Oxidation

Abstract. Atmospherically abundant, volatile water-soluble organic compounds formed through gas-phase chemistry (e.g., glyoxal (C2), methylglyoxal (C3), and acetic acid) have great potential to form secondary organic aerosol (SOA) via aqueous chemistry in clouds, fogs, and wet aerosols. This paper (1) provides chemical insights into aqueous-phase OH-radical-initiated reactions leading to SOA formation from methylglyoxal and (2) uses this and a previously published glyoxal mechanism (Lim et al., 2010) to provide SOA yields for use in chemical transport models. Detailed reaction mechanisms including peroxy radical chemistry and a full kinetic model for aqueous photochemistry of acetic acid and methylglyoxal are developed and validated by comparing simulations with the experimental results from previous studies (Tan et al., 2010, 2012). This new methylglyoxal model is then combined with the previous glyoxal model (Lim et al., 2010), and is used to simulate the profiles of products and to estimate SOA yields. At cloud-relevant concentrations (~ 10−6 − ~ 10−3 M; Munger et al., 1995) of glyoxal and methylglyoxal, the major photooxidation products are oxalic acid and pyruvic acid, and simulated SOA yields (by mass) are ~ 120% for glyoxal and ~ 80% for methylglyoxal. During droplet evaporation oligomerization of unreacted methylglyoxal/glyoxal that did not undergo aqueous photooxidation could enhance yields. In wet aerosols, where total dissolved organics are present at much higher concentrations (~ 10 M), the major oxidation products are oligomers formed via organic radical–radical reactions, and simulated SOA yields (by mass) are ~ 90% for both glyoxal and methylglyoxal. Non-radical reactions (e.g., with ammonium) could enhance yields.

Glyoxal secondary organic aerosol chemistry: effects of dilute nitrate and ammonium and support for organic radical–radical oligomer formation

2013 ◽  
Vol 10 (3) ◽  
pp. 158 ◽  
Author(s):  
Jeffrey R. Kirkland ◽  
Yong B. Lim ◽  
Yi Tan ◽  
Katye E. Altieri ◽  
Barbara J. Turpin
Keyword(s):  
Secondary Organic Aerosol ◽  
Inorganic Nitrogen ◽  
Radical Reaction ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Organic Radical ◽  
Oh Radical ◽  
Radical Oxidation ◽  
Oligomer Formation ◽  
First Time

Environmental context Atmospheric waters (clouds, fogs and wet aerosols) are media in which gases can be converted into particulate matter. This work explores aqueous transformations of glyoxal, a water-soluble gas with anthropogenic and biogenic sources. Results provide new evidence in support of previously proposed chemical mechanisms. These mechanisms are beginning to be incorporated into transport models that link emissions to air pollution concentrations and behaviour. Abstract Glyoxal (GLY) is ubiquitous in the atmosphere and an important aqueous secondary organic aerosol (SOA) precursor. At dilute (cloud-relevant) organic concentrations, OH• radical oxidation of GLY has been shown to produce oxalate. GLY has also been used as a surrogate species to gain insight into radical and non-radical reactions in wet aerosols, where organic and inorganic concentrations are very high (in the molar region). The work herein demonstrates, for the first time, that tartarate forms from GLY+OH•. Tartarate is a key product in a previously proposed organic radical–radical reaction mechanism for oligomer formation from GLY oxidation. Previously published model predictions that include this GLY oxidation pathway suggest that oligomers are major products of OH• radical oxidation at the high organic concentrations found in wet aerosols. The tartarate measurements herein provide support for this proposed oligomer formation mechanism. This paper also demonstrates, for the first time, that dilute (cloud or fog-relevant) concentrations of inorganic nitrogen (i.e. ammonium and nitrate) have little effect on the GLY+OH• chemistry leading to oxalate formation in clouds. This, and results from previous experiments conducted with acidic sulfate, increase confidence that the currently understood dilute GLY+OH• chemistry can be used to predict GLY SOA formation in clouds and fogs. It should be recognised that organic–inorganic interactions can play an important role in droplet evaporation chemistry and in wet aerosols. The chemistry leading to SOA formation in these environments is complex and remains poorly understood.

scholarly journals Chemical Characterization of Secondary Organic Aerosol at a Rural Site in the Southeastern U.S.: Insights from Simultaneous HR-ToF-AMS and FIGAERO-CIMS Measurements

2020 ◽  
Author(s):  
Yunle Chen ◽  
Masayuki Takeuchi ◽  
Theodora Nah ◽  
Lu Xu ◽  
Manjula R. Canagaratna ◽  
...  
Keyword(s):  
High Resolution ◽  
Mass Spectrometer ◽  
Secondary Organic Aerosol ◽  
Time Of Flight ◽  
Organic Aerosol ◽  
Rural Site ◽  
Organic Nitrate ◽  
Ionization Mass ◽  
Resolution Time ◽  
Radical Oxidation

Abstract. The formation and evolution of secondary organic aerosol (SOA) was investigated at Yorkville, GA, in late summer (mid-August ~ mid-October, 2016). Organic aerosol (OA) composition was measured using two on-line mass spectrometry instruments, the high-resolution time-of-flight aerosol mass spectrometer (AMS) and the Filter Inlet for Gases and AEROsols coupled to a high-resolution time-of-flight iodide-adduct chemical ionization mass spectrometer (FIGAERO-CIMS). Through analysis of speciated organics data from FIGAERO-CIMS and factorization analysis of data obtained from both instruments, we observed notable SOA formation from isoprene and monoterpenes during both day and night. Specifically, in addition to isoprene epoxydiols (IEPOX) uptake, we identified isoprene SOA formation via hydroxyl hydroperoxide oxidation (ISOPOOH oxidation via non-IEPOX pathways) and isoprene organic nitrate formation via photooxidation in the presence of NOx and nitrate radical oxidation. Monoterpenes were found to be the most important SOA precursors at night. We observed significant contributions from highly-oxidized acid-like compounds to the aged OA factor from FIGAERO-CIMS. Taken together, our results showed that FIGAERO-CIMS measurements are highly complementary to the extensively used AMS factorization analysis, and together they provide more comprehensive insights into OA sources and composition.

Secondary organic aerosol formation from the photochemical reaction of isoprene with OH radical

2011 ◽  
Vol 41 (7) ◽  
pp. 1206-1214 ◽  
Author(s):  
Wei WANG ◽  
Ying LIU ◽  
ChunMei GENG ◽  
ShaSha DU ◽  
BaoHui YIN ◽  
...  
Keyword(s):  
Photochemical Reaction ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Oh Radical ◽  
Aerosol Formation ◽  
Secondary Organic Aerosol Formation

scholarly journals Atmospheric oxidation of isoprene and 1,3-butadiene: influence of aerosol acidity and relative humidity on secondary organic aerosol

2015 ◽  
Vol 15 (7) ◽  
pp. 3773-3783 ◽  
Author(s):  
M. Lewandowski ◽  
M. Jaoui ◽  
J. H. Offenberg ◽  
J. D. Krug ◽  
T. E. Kleindienst
Keyword(s):  
Organic Carbon ◽  
Secondary Organic Aerosol ◽  
Absolute Humidity ◽  
Organic Aerosol ◽  
Photochemical Oxidation ◽  
Pronounced Increase ◽  
Acid Sensitivity ◽  
Aerosol Acidity ◽  
Acidic Sulfate ◽  
Secondary Organic Carbon

Abstract. The effects of acidic seed aerosols on the formation of secondary organic aerosol (SOA) have been examined in a number of previous studies, several of which have observed strong linear correlations between the aerosol acidity (measured as nmol H+ m−3 air sample volume) and the percent change in secondary organic carbon (SOC). The measurements have used several precursor compounds representative of different classes of biogenic hydrocarbons including isoprene, monoterpenes, and sesquiterpenes. To date, isoprene has displayed the most pronounced increase in SOC, although few measurements have been conducted with anthropogenic hydrocarbons. In the present study, we examine several aspects of the effect of aerosol acidity on the secondary organic carbon formation from the photooxidation of 1,3-butadiene, and extend the previous analysis of isoprene. The photooxidation products measured in the absence and presence of acidic sulfate aerosols were generated either through photochemical oxidation of SO2 or by nebulizing mixtures of ammonium sulfate and sulfuric acid into a 14.5 m3 smog chamber system. The results showed that, like isoprene and β-caryophyllene, 1,3-butadiene SOC yields linearly correlate with increasing acidic sulfate aerosol. The observed acid sensitivity of 0.11% SOC increase per nmol m−3 increase in H+ was approximately a factor of 3 less than that measured for isoprene. The results also showed that the aerosol yield decreased with increasing humidity for both isoprene and 1,3-butadiene, although to different degrees. Increasing the absolute humidity from 2 to 12 g m−3 reduced the 1,3-butadiene yield by 45% and the isoprene yield by 85%.

scholarly journals Importance of secondary organic aerosol formation of <i>α</i>-pinene, limonene, and <i>m</i>-cresol comparing day- and nighttime radical chemistry

2021 ◽  
Vol 21 (11) ◽  
pp. 8479-8498
Author(s):  
Anke Mutzel ◽  
Yanli Zhang ◽  
Olaf Böge ◽  
Maria Rodigast ◽  
Agata Kolodziejczyk ◽  
...  
Keyword(s):  
Mass Fraction ◽  
Secondary Organic Aerosol ◽  
Radical Reaction ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Oh Radicals ◽  
Oh Radical ◽  
Aerosol Formation ◽  
Formation Potential ◽  
Dry Conditions

Abstract. The oxidation of biogenic and anthropogenic compounds leads to the formation of secondary organic aerosol mass (SOA). The present study aims to investigate α-pinene, limonene, and m-cresol with regards to their SOA formation potential dependent on relative humidity (RH) under night- (NO3 radicals) and daytime conditions (OH radicals) and the resulting chemical composition. It was found that SOA formation potential of limonene with NO3 under dry conditions significantly exceeds that of the OH-radical reaction, with SOA yields of 15–30 % and 10–21 %, respectively. Additionally, the nocturnal SOA yield was found to be very sensitive towards RH, yielding more SOA under dry conditions. In contrast, the SOA formation potential of α-pinene with NO3 slightly exceeds that of the OH-radical reaction, independent from RH. On average, α-pinene yielded SOA with about 6–7 % from NO3 radicals and 3–4 % from OH-radical reaction. Surprisingly, unexpectedly high SOA yields were found for m-cresol oxidation with OH radicals (3–9 %), with the highest yield under elevated RH (9 %), which is most likely attributable to a higher fraction of 3-methyl-6-nitro-catechol (MNC). While α-pinene and m-cresol SOA was found to be mainly composed of water-soluble compounds, 50–68 % of nocturnal SOA and 22–39 % of daytime limonene SOA are water-insoluble. The fraction of SOA-bound peroxides which originated from α-pinene varied between 2 and 80 % as a function of RH. Furthermore, SOA from α-pinene revealed pinonic acid as the most important particle-phase constituent under day- and nighttime conditions with a fraction of 1–4 %. Other compounds detected are norpinonic acid (0.05–1.1 % mass fraction), terpenylic acid (0.1–1.1 % mass fraction), pinic acid (0.1–1.8 % mass fraction), and 3-methyl-1,2,3-tricarboxylic acid (0.05–0.5 % mass fraction). All marker compounds showed higher fractions under dry conditions when formed during daytime and showed almost no RH effect when formed during night.

scholarly journals Self-limited uptake of α-pinene-oxide to acidic aerosol: the effects of liquid-liquid phase separation and implications for the formation of secondary organic aerosol and organosulfates from epoxides

2013 ◽  
Vol 13 (3) ◽  
pp. 7151-7174
Author(s):  
G. T. Drozd ◽  
J. L. Woo ◽  
V. F. McNeill
Keyword(s):  
Phase Separation ◽  
Liquid Phase ◽  
Partition Coefficients ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Organic Content ◽  
Liquid Phase Separation ◽  
Wide Range ◽  
Acidic Sulfate ◽  
Liquid Liquid Phase Separation

Abstract. The reactive uptake of α-pinene oxide (αPO) to acidic sulfate aerosol was studied under humid conditions in order to gain insight into the effects of liquid-liquid phase separation on aerosol heterogeneous chemistry and further elucidate the formation of secondary organic aerosol and organosulfates from epoxides. A continuous flow environmental chamber was used to monitor changes in diameter of monodisperse, deliquesced, acidic sulfate particles exposed to αPO at 30 and 50% RH. In order to induce phase separation and probe potential limits to particle growth from acidic uptake, αPO was introduced over a wide range of concentrations, from 200 ppb to 5 ppm. Uptake was observed to be highly dependent on initial aerosol pH. Significant uptake of αPO to aerosol was observed with initial pH < 0. When exposed to 200 ppb αPO, aerosol with pH = −1 doubled in volume, and 6% volume growth was observed at pH = 0. Aerosol with pH = 1 showed no growth. The extreme acidity required for efficient αPO uptake suggests that this chemistry is typically not a major route to formation of aerosol mass or organosulfates in the atmosphere. Partition coefficients (Kp) ranged from 0.2–1.6 × 10−4 m3 μg−1 and were correlated to initial particle acidity and particle organic content; particles with higher organic content had lower partition coefficients. Effective uptake coefficients (γ) ranged from 0.4 to 4.7 × 10−5 and are much lower than recently reported for uptake to bulk solutions. In experiments in which αPO was added to bulk H2SO4 solutions, phase separation was observed for mass loadings similar to those observed with particles, and product distributions were dependent on acid concentration. Liquid-liquid phase separation in bulk experiments, along with our observations of decreased uptake to particles with the largest growth factors, suggest an organic coating forms upon uptake to particles, limiting reactive uptake.

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