Time Scales for Gas-Particle Partitioning Equilibration of Secondary Organic Aerosol Formed from Alpha-Pinene Ozonolysis

2013 ◽  
Vol 47 (11) ◽  
pp. 5588-5594 ◽  
Author(s):  
Rawad Saleh ◽  
Neil M. Donahue ◽  
Allen L. Robinson
Keyword(s):  
Time Scales ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Alpha Pinene

scholarly journals Novel Pathway of SO<sub>2</sub> Oxidation in the Atmosphere: Reactions with Monoterpene Ozonolysis Intermediates and Secondary Organic Aerosol

2017 ◽  
Author(s):  
Jianhuai Ye ◽  
Jonathan P. D. Abbatt ◽  
Arthur W. H. Chan
Keyword(s):  
Secondary Organic Aerosol ◽  
Synergistic Effects ◽  
Organic Aerosol ◽  
Experimental Chamber ◽  
Organic Peroxides ◽  
So2 Oxidation ◽  
Loss Mechanism ◽  
Alpha Pinene ◽  
Criegee Intermediates ◽  
Dry Conditions

Abstract. Ozonolysis of monoterpenes is an important source of atmospheric biogenic secondary organic aerosol (BSOA). While enhanced BSOA formation has been associated with sulfate-rich conditions, the underlying mechanisms remain poorly understood. In this work, the interactions between SO2 and reactive intermediates from monoterpene ozonolysis were investigated under different humidity conditions (10 % vs. 50 %). Chamber experiments were conducted with ozonolysis of alpha-pinene or limonene in the presence of SO2. Limonene SOA formation was enhanced in the presence of SO2, while no significant changes in SOA yields were observed during alpha-pinene ozonolysis. Under dry conditions, SO2 primarily reacted with stabilized Criegee Intermediates (sCI) produced from ozonolysis, but at 50 % RH, heterogeneous uptake of SO2 onto organic aerosol was found to be the dominant sink of SO2, likely owing to reactions between SO2 and organic peroxides. This SO2 loss mechanism to organic peroxides in SOA has not previously been identified in experimental chamber study. Organosulfates were detected and identified using electrospray ionization-ion mobility time of flight mass spectrometer (ESI-IMS-TOF) when SO2 was present in the experiments. Our results demonstrate the synergistic effects between BSOA formation and SO2 oxidation through sCI chemistry and SO2 uptake onto organic aerosol and illustrate the importance of considering the chemistry of organic and sulfur-containing compounds holistically to properly account for their reactive sinks.

scholarly journals The nitrate radical (NO<sub>3</sub>) oxidation of alpha-pinene is a significant source of secondary organic aerosol and organic nitrogen under simulated ambient nighttime conditions

2021 ◽  
Author(s):  
Kelvin H. Bates ◽  
Guy J. P. Burke ◽  
James D. Cope ◽  
Tran B. Nguyen
Keyword(s):  
Organic Nitrogen ◽  
Secondary Organic Aerosol ◽  
Experimental Studies ◽  
Branching Ratio ◽  
Organic Aerosol ◽  
Reactive Nitrogen ◽  
Composition Analysis ◽  
Southeast United States ◽  
Nitrogen Budgets ◽  
Alpha Pinene

Abstract. The reaction of α-pinene with NO3 is an important sink of both α-pinene and NO3 at night in regions with mixed biogenic and anthropogenic emissions; however, there is debate on its importance for secondary organic aerosol (SOA) and reactive nitrogen budgets in the atmosphere. Previous experimental studies have generally observed low or zero SOA formation, often due to excessive [NO3] conditions. Here, we characterize the SOA and organic nitrogen formation from α-pinene + NO3 as a function of nitrooxy peroxy (nRO2) radical fates with HO2, NO, NO3, and RO2 in an atmospheric chamber. We show that SOA yields are not small when the nRO2 fate distribution in the chamber mimics that in the atmosphere, and the formation of pinene nitrooxy hydroperoxide (PNP) and related organonitrates in the ambient can be reproduced. Nearly all SOA from α-pinene + NO3 chemistry derives from the nRO2 + nRO2 pathway, which alone has an SOA mass yield of 65 (±9) %. Molecular composition analysis shows that particulate nitrates are a large (60–70 %) portion of the SOA, and that dimer formation is the primary mechanism of SOA production from α-pinene + NO3 under simulated nighttime conditions. We estimate an average nRO2 + nRO2 → ROOR branching ratio of ~18 %. Synergistic dimerization between nRO2 and RO2 derived from ozonolysis and OH oxidation also contribute to SOA formation, and should be considered in models. We report a 58 (±20) % molar yield of PNP from the nRO2 + HO2 pathway. Applying these laboratory constraints to model simulations of summertime conditions observed in the Southeast United States (where 80 % of α-pinene is lost via NO3 oxidation, leading to 20 % nRO2 + nRO2 and 45 % nRO2 + HO2) , we estimate yields of 13% SOA and 9% particulate nitrate by mass, and 26 % PNP by mole, from α-pinene + NO3 in the ambient. These results suggest that α-pinene + NO3 significantly contributes to the SOA budget, and likely constitutes a major removal pathway of reactive nitrogen from the nighttime boundary layer in mixed biogenic/anthropogenic areas.

a-pinene autoxidation at sub-second time-scales

2020 ◽  
Author(s):  
Matti Rissanen ◽  
Shawon Barua ◽  
Jordan Krechmer ◽  
Theo Kurtén ◽  
Siddharth Iyer
Keyword(s):  
Reaction Time ◽  
Organic Compounds ◽  
Time Scales ◽  
Chemical Ionization ◽  
Flow Reactor ◽  
Secondary Organic Aerosol ◽  
Computational Study ◽  
Peroxy Radical ◽  
Organic Aerosol ◽  
Ionization Mass

&lt;p&gt;Atmospheric aerosols impact climate and health. Most of the smallest atmospheric nanoparticles are formed by oxidation of volatile organic compounds (VOC) and subsequent condensation of resulting low-volatile vapors. Biogenic terpenes are the largest atmospheric secondary organic aerosol (SOA) source, and among these, a-pinene likely the single most important compound.&lt;/p&gt;&lt;p&gt;&amp;#160;Recently, autoxidation changed the paradigm of long processing time-scales in the formation of SOA [1, 2]. Previous experiments with cyclic unsaturated compounds have indicated the autoxidation to be very rapid, forming compounds with even 10 O-atoms infused to the carbon structure in a few seconds timeframe [3-6]. Berndt et al. noted that the whole process was apparently finished already at about 1.5 seconds reaction time in cyclohexene ozonolysis initiated autoxidation, indicated by the &amp;#8220;frozen&amp;#8221; peroxy radical product distribution beyond this reaction time [4].&lt;/p&gt;&lt;p&gt;Here we performed sub-second time-scale flow reactor experiments of a-pinene ozonolysis initiated autoxidation under ambient atmospheric conditions to constrain the timeframe needed to form the first highly-oxidized reaction products, and to inspect the peroxy radical dynamics at significantly shorter reaction times than have been previously possible. The shortest achievable reaction time was around 0.1 seconds and was enabled by the new Multi-scheme chemical IONization (MION) inlet setup [7]. Nitrate and bromide were used as reagent ions in this work.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;/p&gt;&lt;ol&gt;&lt;li&gt;J. D. Crounse, et al. Autoxidation of Organic Compounds in the Atmosphere, J. Phys. Chem. Lett., 2013, 4, 3513-3520.&lt;/li&gt; &lt;li&gt;M. Ehn, et al. A large source of low-volatility secondary organic aerosol, Nature, 2014, 506, 476-479.&lt;/li&gt; &lt;li&gt;M. P. Rissanen, et al. The formation of highly oxidized multifunctional products in the ozonolysis of cyclohexene, J. Am. Chem. Soc., 2014, 136, 15596-15606.&lt;/li&gt; &lt;li&gt;T. Berndt, et al. Gas-Phase Ozonolysis of Cycloalkenes: Formation of Highly Oxidized RO&lt;sub&gt;2&lt;/sub&gt; Radicals and Their Reactions with NO, NO&lt;sub&gt;2&lt;/sub&gt;, SO&lt;sub&gt;2&lt;/sub&gt;, and Other RO&lt;sub&gt;2&lt;/sub&gt; Radicals, J. Phys. Chem. A, 2015, 119, 10336-10348.&lt;/li&gt; &lt;li&gt;M. P. Rissanen, et al. Kulmala, Effects of Chemical Complexity on the Autoxidation Mechanisms of Endocyclic Alkene Ozonolysis Products: From Methylcyclohexenes toward Understanding &amp;#945;-Pinene, J. Phys. Chem. A, 2015, 119, 4633-4650.&lt;/li&gt; &lt;li&gt;T. Kurt&amp;#233;n, et al. Computational Study of Hydrogen Shifts and Ring-Opening Mechanisms in &amp;#945;-Pinene Ozonolysis Products, J. Phys. Chem. A, 2015, 119, 11366-11375.&lt;/li&gt; &lt;li&gt;M. P. Rissanen, et al. Multi-scheme chemical ionization inlet (MION) for fast switching of reagent ion chemistry in atmospheric pressure chemical ionization mass spectrometry (CIMS) applications, Atmos. Meas. Tech., 2019, 12, 6635-6646.&lt;/li&gt; &lt;/ol&gt;

The effect of sub-zero temperature on the formation and composition of secondary organic aerosol from ozonolysis of alpha-pinene

2017 ◽  
Vol 19 (10) ◽  
pp. 1220-1234 ◽  
Author(s):  
K. Kristensen ◽  
L. N. Jensen ◽  
M. Glasius ◽  
M. Bilde,
Keyword(s):  
Reaction Temperature ◽  
Low Temperatures ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Zero Temperature ◽  
Alpha Pinene

Composition of aerosol from oxidation of alpha-pinene is affected by reaction temperature with decreased contribution from low volatile dimer esters at low temperatures.

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