Bouncier Particles at Night: Biogenic Secondary Organic Aerosol Chemistry and Sulfate Drive Diel Variations in the Aerosol Phase in a Mixed Forest

2019 ◽  
Vol 53 (9) ◽  
pp. 4977-4987 ◽  
Author(s):  
Jonathan H. Slade ◽  
Andrew P. Ault ◽  
Alexander T. Bui ◽  
Jenna C. Ditto ◽  
Ziying Lei ◽  
...  
Keyword(s):  
Secondary Organic Aerosol ◽  
Mixed Forest ◽  
Organic Aerosol ◽  
Aerosol Chemistry ◽  
Diel Variations

scholarly journals Formation of hydroxyl radicals from photolysis of secondary organic aerosol material

2015 ◽  
Vol 15 (4) ◽  
pp. 4117-4143 ◽  
Author(s):  
K. M. Badali ◽  
S. Zhou ◽  
D. Aljawhary ◽  
M. Antiñolo ◽  
W. J. Chen ◽  
...  
Keyword(s):  
Hydroxyl Radicals ◽  
Secondary Organic Aerosol ◽  
Formation Rate ◽  
Cumene Hydroperoxide ◽  
Organic Aerosol ◽  
Oh Radicals ◽  
Aerosol Chemistry ◽  
Peroxide Content ◽  
Radical Trap ◽  
Organic Hydroperoxides

Abstract. This paper demonstrates that OH radicals are formed by photolysis of secondary organic aerosol (SOA) material formed by terpene ozonolysis. The SOA aerosol is collected on filters, dissolved in water containing a radical trap (benzoic acid), and then exposed to ultraviolet light in a photochemical reactor. The OH formation rates, which are similar for both α-pinene and limonene SOA, are measured from the formation rate of p-hydroxybenzoic acid as measured using offline HPLC analysis. To evaluate whether the OH is formed by photolysis of H2O2 or organic hydroperoxides (ROOH), the peroxide content of the SOA was measured using the horseradish peroxidase-dichlorofluorescein (HRP-DCF) assay, which was calibrated using H2O2. The OH formation rates from SOA are five times faster than from the photolysis of H2O2 solutions whose concentrations correspond to the peroxide content of the SOA solutions assuming that the HRP-DCF signal arises from H2O2 alone. The higher rates of OH formation from SOA are likely due to ROOH photolysis. This result is substantiated by photolysis experiments conducted with t-butyl hydroperoxide and cumene hydroperoxide which produce over three times more OH than photolysis of equivalent concentrations of H2O2. Relative to the peroxide level in the SOA, the quantum yield for OH generation from α-pinene SOA is 0.8 ± 0.4. This is the first demonstration of an efficient photolytic source of OH in SOA, one that may affect both cloudwater and aerosol chemistry.

scholarly journals Formation of hydroxyl radicals from photolysis of secondary organic aerosol material

2015 ◽  
Vol 15 (14) ◽  
pp. 7831-7840 ◽  
Author(s):  
K. M. Badali ◽  
S. Zhou ◽  
D. Aljawhary ◽  
M. Antiñolo ◽  
W. J. Chen ◽  
...  
Keyword(s):  
Secondary Organic Aerosol ◽  
Formation Rate ◽  
Cumene Hydroperoxide ◽  
Organic Aerosol ◽  
Oh Radicals ◽  
Aerosol Chemistry ◽  
Peroxide Content ◽  
Radical Trap ◽  
Organic Hydroperoxides ◽  
Rule Out

Abstract. This paper demonstrates that OH radicals are formed by photolysis of secondary organic aerosol (SOA) material formed by terpene ozonolysis. The SOA is collected on filters, dissolved in water containing a radical trap (benzoic acid), and then exposed to ultraviolet light in a photochemical reactor. The OH formation rates, which are similar for both α-pinene and limonene SOA, are measured from the formation rate of p-hydroxybenzoic acid as measured using offline HPLC analysis. To evaluate whether the OH is formed by photolysis of H2O2 or organic hydroperoxides (ROOH), the peroxide content of the SOA was measured using the horseradish peroxidase-dichlorofluorescein (HRP-DCF) assay, which was calibrated using H2O2. The OH formation rates from SOA are 5 times faster than from the photolysis of H2O2 solutions whose concentrations correspond to the peroxide content of the SOA solutions, assuming that the HRP-DCF signal arises from H2O2 alone. The higher rates of OH formation from SOA are likely due to ROOH photolysis, but we cannot rule out a contribution from secondary processes as well. This result is substantiated by photolysis experiments conducted with t-butyl hydroperoxide and cumene hydroperoxide which produce over 3 times more OH than photolysis of equivalent concentrations of H2O2. Relative to the peroxide level in the SOA and assuming that the peroxides drive most of the ultraviolet absorption, the quantum yield for OH generation from α-pinene SOA is 0.8 ± 0.4. This is the first demonstration of an efficient photolytic source of OH in SOA, one that may affect both cloud water and aerosol chemistry.

Supplementary material to "Isoprene derived secondary organic aerosol in a global aerosol chemistry climate model"

2017 ◽  
Author(s):  
Scarlet Stadtler ◽  
Thomas Kühn ◽  
Sabine Schröder ◽  
Domenico Taraborrelli ◽  
Martin G. Schultz ◽  
...  
Keyword(s):  
Climate Model ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Aerosol Chemistry ◽  
Supplementary Material

scholarly journals Nitrate radical oxidation of <i>γ</i>-terpinene: hydroxy nitrate, total organic nitrate, and secondary organic aerosol yields

2017 ◽  
Vol 17 (14) ◽  
pp. 8635-8650 ◽  
Author(s):  
Jonathan H. Slade ◽  
Chloé de Perre ◽  
Linda Lee ◽  
Paul B. Shepson
Keyword(s):  
Secondary Organic Aerosol ◽  
Mixed Forest ◽  
Organic Aerosol ◽  
High Reactivity ◽  
Organic Nitrate ◽  
Organic Nitrates ◽  
Nitrate Radical ◽  
Particle Phase ◽  
Forest Environment ◽  
Radical Oxidation

Abstract. Polyolefinic monoterpenes represent a potentially important but understudied source of organic nitrates (ONs) and secondary organic aerosol (SOA) following oxidation due to their high reactivity and propensity for multi-stage chemistry. Recent modeling work suggests that the oxidation of polyolefinic γ-terpinene can be the dominant source of nighttime ON in a mixed forest environment. However, the ON yields, aerosol partitioning behavior, and SOA yields from γ-terpinene oxidation by the nitrate radical (NO3), an important nighttime oxidant, have not been determined experimentally. In this work, we present a comprehensive experimental investigation of the total (gas + particle) ON, hydroxy nitrate, and SOA yields following γ-terpinene oxidation by NO3. Under dry conditions, the hydroxy nitrate yield  =  4(+1/−3) %, total ON yield  =  14(+3/−2) %, and SOA yield  ≤  10 % under atmospherically relevant particle mass loadings, similar to those for α-pinene + NO3. Using a chemical box model, we show that the measured concentrations of NO2 and γ-terpinene hydroxy nitrates can be reliably simulated from α-pinene + NO3 chemistry. This suggests that NO3 addition to either of the two internal double bonds of γ-terpinene primarily decomposes forming a relatively volatile keto-aldehyde, reconciling the small SOA yield observed here and for other internal olefinic terpenes. Based on aerosol partitioning analysis and identification of speciated particle-phase ON applying high-resolution liquid chromatography–mass spectrometry, we estimate that a significant fraction of the particle-phase ON has the hydroxy nitrate moiety. This work greatly contributes to our understanding of ON and SOA formation from polyolefin monoterpene oxidation, which could be important in the northern continental US and the Midwest, where polyolefinic monoterpene emissions are greatest.

scholarly journals Nitrate radical oxidation of γ-terpinene: hydroxy nitrate, total organic nitrate, and secondary organic aerosol yields

2017 ◽  
Author(s):  
Jonathan H. Slade ◽  
Chloé de Perre ◽  
Linda Lee ◽  
Paul B. Shepson
Keyword(s):  
Secondary Organic Aerosol ◽  
Mixed Forest ◽  
Organic Aerosol ◽  
High Reactivity ◽  
Organic Nitrate ◽  
Organic Nitrates ◽  
Nitrate Radical ◽  
Particle Phase ◽  
Forest Environment ◽  
Radical Oxidation

Abstract. Polyolefinic monoterpenes represent a potentially important but understudied source of organic nitrates (ON) and secondary organic aerosol (SOA) following oxidation due to their high reactivity and propensity for multi-stage chemistry. Recent modeling work suggests that the oxidation of polyolefinic γ-terpinene can be the dominant source of nighttime ON in a mixed forest environment. However, the ON yields, aerosol partitioning behavior, and SOA yields from γ-terpinene oxidation by the nitrate radical (NO3), an important nighttime oxidant, have not been determined experimentally. In this work, we present a comprehensive experimental investigation of the total (gas + particle) ON, hydroxy nitrate, and SOA yields following γ-terpinene oxidation by NO3. Under dry conditions, the hydroxy nitrate yield = 4(+1/−3) %, total ON yield = 14(+3/−2) %, and SOA yield ≤10% under atmospherically-relevant particle mass loadings, similar to those for α-pinene + NO3. Using a chemical box model, we show that the measured concentrations of NO2 and γ-terpinene hydroxy nitrates can be reliably simulated from α-pinene + NO3 chemistry. This suggests that NO3 addition to either of the two internal double bonds of γ-terpinene primarily decomposes forming a relatively volatile keto–aldehyde, reconciling the small SOA yield observed here and for other internal olefinic terpenes. Based on aerosol partitioning analysis and identification of speciated particle-phase ON applying high-resolution liquid chromatography–mass spectrometry, we estimate that a significant fraction of the particle-phase ON has the hydroxy nitrate moiety. This work greatly contributes to our understanding of ON and SOA formation from polyolefin monoterpene oxidation, which could be important in the northern continental U.S. and Midwest, where polyolefinic monoterpene emissions are greatest.

scholarly journals Contributions of individual reactive biogenic volatile organic compounds to organic nitrates above a mixed forest

2012 ◽  
Vol 12 (7) ◽  
pp. 17031-17086 ◽  
Author(s):  
K. A. Pratt ◽  
L. H. Mielke ◽  
P. B. Shepson ◽  
A. M. Bryan ◽  
A. L. Steiner ◽  
...  
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Secondary Organic Aerosol ◽  
Mixed Forest ◽  
Organic Aerosol ◽  
Oxidation Products ◽  
Organic Nitrates ◽  
Aerosol Formation ◽  
Biogenic Volatile Organic Compounds ◽  
Volatile Organic

Abstract. Biogenic volatile organic compounds (BVOCs) can react in the atmosphere to form organic nitrates, which serve as NOx (NO + NO2) reservoirs, impacting ozone and secondary organic aerosol production, the oxidative capacity of the atmosphere, and nitrogen availability to ecosystems. To examine the contributions of biogenic emissions and the formation and fate of organic nitrates in a forest environment, we simulated the oxidation of 57 individual BVOCs emitted from a rural mixed forest in Northern Michigan. Of the total simulated organic nitrates, monoterpenes contributed ~70% in the early morning at ~12 m above the forest canopy when isoprene emissions were low. In the afternoon, when vertical mixing and isoprene nitrate production were highest, the simulated contribution of isoprene-derived organic nitrates was greater than 90% at all altitudes, with the concentration of secondary isoprene nitrates increasing with altitude. Key BVOC-oxidant reactions were identified for future laboratory and field investigations into reaction rate constants, yields, and speciation of oxidation products. Forest succession, wherein aspen trees are being replaced by pine and maple trees, was predicted to lead to increased afternoon concentrations of monoterpene-derived organic nitrates. This further underscores the need to understand the formation and fate of these species, which have different chemical pathways and oxidation products compared to isoprene-derived organic nitrates and can lead to secondary organic aerosol formation.

scholarly journals Secondary organic aerosol formation from biomass burning emissions

2019 ◽  
Author(s):  
Christopher Y. Lim ◽  
David H. Hagan ◽  
Matthew M. Coggon ◽  
Abigail R. Koss ◽  
Kanako Sekimoto ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Secondary Organic Aerosol ◽  
Total Concentration ◽  
Organic Aerosol ◽  
Oh Radicals ◽  
Aerosol Formation ◽  
Atmospheric Aging ◽  
Aerosol Mass ◽  
Photochemical Aging ◽  
Organic Gases

Abstract. Biomass burning is an important source of aerosol and trace gases to the atmosphere, but how these emissions change chemically during their lifetimes is not fully understood. As part of the Fire Influence on Regional and Global Environments Experiment (FIREX 2016), we investigated the effect of photochemical aging on biomass burning organic aerosol (BBOA), with a focus on fuels from the western United States. Emissions were sampled into a small (150 L) environmental chamber and photochemically aged via the addition of ozone and irradiation by 254 nm light. While some fraction of species undergoes photolysis, the vast majority of aging occurs via reaction with OH radicals, with total OH exposures corresponding to the equivalent of up to 10 days of atmospheric oxidation. For all fuels burned, large and rapid changes are seen in the ensemble chemical composition of BBOA, as measured by an aerosol mass spectrometer (AMS). Secondary organic aerosol (SOA) formation is seen for all aging experiments and continues to grow with increasing OH exposure, but the magnitude of the SOA formation is highly variable between experiments. This variability can be explained well by a combination of experiment-to-experiment differences in OH exposure and the total concentration of non-methane organic gases (NMOGs) in the chamber before oxidation, measured by PTR-ToF-MS (r2 values from 0.64 to 0.83). From this relationship, we calculate the fraction of carbon from biomass burning NMOGs that is converted to SOA as a function of equivalent atmospheric aging time, with carbon yields ranging from 24 ± 4 % after 6 hours to 56 ± 9 % after 4 days.

scholarly journals Aging of atmospheric aerosols and the role of iron in catalyzing brown carbon formation

2021 ◽  
Author(s):  
Hind A. A. Al-Abadleh
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Atmospheric Aerosols ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Atmospheric Oxidation ◽  
Carbon Formation ◽  
Brown Carbon ◽  
Volatile Organic

Extensive research has been done on the processes that lead to the formation of secondary organic aerosol (SOA) including atmospheric oxidation of volatile organic compounds (VOCs) from biogenic and anthropogenic...

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