Secondary organic aerosol from chlorine-initiated oxidation of isoprene

Organic Aerosol ◽

Oxidative Capacity ◽

Oxidation Products ◽

Ionization Mass ◽

Photo Oxidation ◽

Wide Range ◽

Chlorine Radicals ◽

Isoprene Oxidation ◽

Isoprene Oxidation Products

Abstract. Recent studies have found inland concentrations of reactive chlorine species to be higher than expected, suggesting that atmospheric chlorine chemistry is more extensive than previously thought. Chlorine radicals can interact with HOx radicals and nitrogen oxides (NOx) to alter the oxidative capacity of the atmosphere. They are known to rapidly oxidize a wide range of volatile organic compounds (VOC) found in the atmosphere, yet little is known about secondary organic aerosol (SOA) formation from chlorine-initiated photo-oxidation and its atmospheric implications. Environmental chamber experiments were carried out under low-NOx conditions with isoprene and chlorine as primary VOC and oxidant sources. Upon complete isoprene consumption, observed SOA yields ranged from 8 % to 36 %, decreasing with extended photo-oxidation and SOA aging. A High-Resolution Time-of-Flight Chemical Ionization Mass Spectrometer was used to determine the molecular composition of gas-phase species using iodide-water and hydronium-water ionization. Ions consistent with isoprene-derived epoxydiol (IEPOX) and other common OH-isoprene oxidation products were observed, evident of secondary OH production and resulting chemistry from Cl-initiated reactions.

Secondary organic aerosol from chlorine-initiated oxidation of isoprene

10.5194/acp-17-13491-2017 ◽

2017 ◽

Vol 17 (22) ◽

pp. 13491-13508 ◽

Cited By ~ 22

Author(s):

Dongyu S. Wang ◽

Lea Hildebrandt Ruiz

Keyword(s):

Hypochlorous Acid ◽

Organic Aerosol ◽

Oxidative Capacity ◽

Ionization Mass ◽

Wide Range ◽

Volatile Organic ◽

Chlorine Radicals ◽

Reported Study ◽

Cluster Ionization

Abstract. Recent studies have found concentrations of reactive chlorine species to be higher than expected, suggesting that atmospheric chlorine chemistry is more extensive than previously thought. Chlorine radicals can interact with hydroperoxy (HOx) radicals and nitrogen oxides (NOx) to alter the oxidative capacity of the atmosphere. They are known to rapidly oxidize a wide range of volatile organic compounds (VOCs) found in the atmosphere, yet little is known about secondary organic aerosol (SOA) formation from chlorine-initiated photooxidation and its atmospheric implications. Environmental chamber experiments were carried out under low-NOx conditions with isoprene and chlorine as primary VOC and oxidant sources. Upon complete isoprene consumption, observed SOA yields ranged from 7 to 36 %, decreasing with extended photooxidation and SOA aging. Formation of particulate organochloride was observed. A high-resolution time-of-flight chemical ionization mass spectrometer was used to determine the molecular composition of gas-phase species using iodide–water and hydronium–water cluster ionization. Multi-generational chemistry was observed, including ions consistent with hydroperoxides, chloroalkyl hydroperoxides, isoprene-derived epoxydiol (IEPOX), and hypochlorous acid (HOCl), evident of secondary OH production and resulting chemistry from Cl-initiated reactions. This is the first reported study of SOA formation from chlorine-initiated oxidation of isoprene. Results suggest that tropospheric chlorine chemistry could contribute significantly to organic aerosol loading.

Secondary organic aerosol yields from cloud-processing of isoprene oxidation products

Geophysical Research Letters ◽

10.1029/2007gl031828 ◽

2008 ◽

Vol 35 (2) ◽

Cited By ~ 203

Author(s):

Barbara Ervens ◽

Annmarie G. Carlton ◽

Barbara J. Turpin ◽

Katye E. Altieri ◽

Sonia M. Kreidenweis ◽

...

Keyword(s):

Organic Aerosol ◽

Oxidation Products ◽

Cloud Processing ◽

Isoprene Oxidation ◽

Isoprene Oxidation Products

Isoprene oxidation by nitrate radical: alkyl nitrate and secondary organic aerosol yields

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-9-8857-2009 ◽

2009 ◽

Vol 9 (2) ◽

pp. 8857-8902 ◽

Cited By ~ 4

Author(s):

A. W. Rollins ◽

A. Kiendler-Scharr ◽

J. Fry ◽

T. Brauers ◽

S. S. Brown ◽

...

Keyword(s):

First Generation ◽

Model Simulation ◽

Effective Rate Constant ◽

Organic Aerosol ◽

Effective Rate ◽

Oxidation Products ◽

Alkyl Nitrates ◽

Alkyl Nitrate ◽

Isoprene Oxidation

Abstract. Alkyl nitrates and secondary organic aerosol (SOA) produced during the oxidation of isoprene by nitrate radicals has been observed in the SAPHIR chamber. We find the yield of nitrates is 70±8% from the isoprene+NO3 reaction, and the yield for secondary dinitrates produced in the reaction of primary isoprene nitrates with NO3 is 40±20%. We find an effective rate constant for reaction of NO3 with the group of first generation oxidation products to be 7×10−14 cm3 s−1. At the low total organic aerosol concentration in the chamber (max ≈0.6 μg m−3) we observed a mass yield (ΔSOA mass/Δisoprene mass) of 2% for the entire 16 h experiment. However a comparison of the timing of the observed SOA production to a box model simulation of first and second generation oxidation products shows that the yield from the first generation products was <0.2% while the further oxidation of the initial products leads to a yield of 10% (defined as ΔSOA/Δisoprene2x where Δisoprene2x is the mass of isoprene which reacted twice with NO3). The SOA yield of 10% is consistent with equilibrium partitioning of highly functionalized C5 products of isoprene oxidation.

Investigating the use of secondary organic aerosol as seed particles in simulation chamber experiments

10.5194/acp-11-5917-2011 ◽

2011 ◽

Vol 11 (12) ◽

pp. 5917-5929 ◽

Cited By ~ 34

Author(s):

J. F. Hamilton ◽

M. Rami Alfarra ◽

K. P. Wyche ◽

M. W. Ward ◽

A. C. Lewis ◽

...

Keyword(s):

Mass Spectrometry ◽

Organic Aerosol ◽

Oxidation Products ◽

Ion Cyclotron Resonance ◽

Photo Oxidation ◽

Seed Particles ◽

Aerosol Mass ◽

Seed Aerosol ◽

Limonene Oxidation

Abstract. The use of β-caryophyllene secondary organic aerosol particles as seeds for smog chamber simulations has been investigated. A series of experiments were carried out in the Manchester photochemical chamber as part of the Aerosol Coupling in the Earth System (ACES) project to study the effect of seed particles on the formation of secondary organic aerosol (SOA) from limonene photo-oxidation. Rather than use a conventional seed aerosol containing ammonium sulfate or diesel particles, a method was developed to use in-situ chamber generated seed particles from β-caryophyllene photo-oxidation, which were then diluted to a desired mass loading (in this case 4–13 μg m−3). Limonene was then introduced into the chamber and oxidised, with the formation of SOA seen as a growth in the size of oxidised organic seed particles from 150 to 325 nm mean diameter. The effect of the partitioning of limonene oxidation products onto the seed aerosol was assessed using aerosol mass spectrometry during the experiment and the percentage of m/z 44, an indicator of degree of oxidation, increased from around 5 to 8 %. The hygroscopicity of the aerosol also changed, with the growth factor for 200 nm particles increasing from less than 1.05 to 1.25 at 90 % RH. The detailed chemical composition of the limonene SOA could be extracted from the complex β-caryophyllene matrix using two-dimensional gas chromatography (GC × GC) and liquid chromatography coupled to mass spectrometry. High resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS) was used to determine exact molecular formulae of the seed and the limonene modified aerosol. The average O:C ratio was seen to increase from 0.32 to 0.37 after limonene oxidation products had condensed onto the organic seed.

Evidence for a significant proportion of Secondary Organic Aerosol from isoprene above a maritime tropical forest

10.5194/acp-11-1039-2011 ◽

2011 ◽

Vol 11 (3) ◽

pp. 1039-1050 ◽

Cited By ~ 123

Author(s):

N. H. Robinson ◽

J. F. Hamilton ◽

J. D. Allan ◽

B. Langford ◽

D. E. Oram ◽

...

Keyword(s):

Significant Proportion ◽

Organic Aerosol ◽

Oxidation Products ◽

Emission Region ◽

Experimental Chamber ◽

Mass Spectral ◽

Aerosol Mass ◽

Isoprene Oxidation ◽

Highly Correlated

Abstract. Isoprene is the most abundant non-methane biogenic volatile organic compound (BVOC), but the processes governing secondary organic aerosol (SOA) formation from isoprene oxidation are only beginning to become understood and selective quantification of the atmospheric particulate burden remains difficult. Organic aerosol above a tropical rainforest located in Danum Valley, Borneo, Malaysia, a high isoprene emission region, was studied during Summer 2008 using Aerosol Mass Spectrometry and offline detailed characterisation using comprehensive two dimensional gas chromatography. Observations indicate that a substantial fraction (up to 15% by mass) of atmospheric sub-micron organic aerosol was observed as methylfuran (MF) after thermal desorption. This observation was associated with the simultaneous measurements of established gas-phase isoprene oxidation products methylvinylketone (MVK) and methacrolein (MACR). Observations of MF were also made during experimental chamber oxidation of isoprene. Positive matrix factorisation of the AMS organic mass spectral time series produced a robust factor which accounts for an average of 23% (0.18 μg m−3), reaching as much as 53% (0.50 μg m−3) of the total oraganic loading, identified by (and highly correlated with) a strong MF signal. Assuming that this factor is generally representative of isoprene SOA, isoprene derived aerosol plays a significant role in the region. Comparisons with measurements from other studies suggest this type of isoprene SOA plays a role in other isoprene dominated environments, albeit with varying significance.

Phase partitioning and volatility of secondary organic aerosol components formed from α-pinene ozonolysis and OH oxidation: the importance of accretion products and other low volatility compounds

10.5194/acp-15-7765-2015 ◽

2015 ◽

Vol 15 (14) ◽

pp. 7765-7776 ◽

Cited By ~ 72

Author(s):

F. D. Lopez-Hilfiker ◽

C. Mohr ◽

M. Ehn ◽

F. Rubach ◽

E. Kleist ◽

...

Keyword(s):

Organic Compounds ◽

Mass Spectrometer ◽

Organic Aerosol ◽

Oxidation Products ◽

Negative Ion ◽

Ionization Mass ◽

Particle Phase ◽

Vapor Pressures ◽

Aerosol Mass

Abstract. We measured a large suite of gas- and particle-phase multi-functional organic compounds with a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) developed at the University of Washington. The instrument was deployed on environmental simulation chambers to study monoterpene oxidation as a secondary organic aerosol (SOA) source. We focus here on results from experiments utilizing an ionization method most selective towards acids (acetate negative ion proton transfer), but our conclusions are based on more general physical and chemical properties of the SOA. Hundreds of compounds were observed in both gas and particle phases, the latter being detected by temperature-programmed thermal desorption of collected particles. Particulate organic compounds detected by the FIGAERO–HR-ToF-CIMS are highly correlated with, and explain at least 25–50 % of, the organic aerosol mass measured by an Aerodyne aerosol mass spectrometer (AMS). Reproducible multi-modal structures in the thermograms for individual compounds of a given elemental composition reveal a significant SOA mass contribution from high molecular weight organics and/or oligomers (i.e., multi-phase accretion reaction products). Approximately 50 % of the HR-ToF-CIMS particle-phase mass is associated with compounds having effective vapor pressures 4 or more orders of magnitude lower than commonly measured monoterpene oxidation products. The relative importance of these accretion-type and other extremely low volatility products appears to vary with photochemical conditions. We present a desorption-temperature-based framework for apportionment of thermogram signals into volatility bins. The volatility-based apportionment greatly improves agreement between measured and modeled gas-particle partitioning for select major and minor components of the SOA, consistent with thermal decomposition during desorption causing the conversion of lower volatility components into the detected higher volatility compounds.

Investigating the use of secondary organic aerosol as seed particles in simulation chamber experiments

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-25117-2010 ◽

2010 ◽

Vol 10 (10) ◽

pp. 25117-25151

Author(s):

J. F. Hamilton ◽

M. Rami Alfarra ◽

K. P. Wyche ◽

M. W. Ward ◽

A. C. Lewis ◽

...

Keyword(s):

Mass Spectrometry ◽

Organic Aerosol ◽

Oxidation Products ◽

Ion Cyclotron Resonance ◽

Photo Oxidation ◽

Seed Particles ◽

Aerosol Mass ◽

Seed Aerosol ◽

Limonene Oxidation

Abstract. The use of β-caryophyllene secondary organic aerosol particles as seeds for smog chamber simulations has been investigated. A series of experiments were carried out in the Manchester photochemical chamber as part of the Aerosol Coupling in the Earth System (ACES) project to study the effect of seed particles on the formation of secondary organic aerosol (SOA) from limonene photo-oxidation. Rather than use a conventional seed aerosol containing ammonium sulphate or diesel particles, a method was developed to use in situ chamber generated seed particles from β-caryophyllene photo-oxidation, which were then diluted to a desired mass loading (in this case 4–13 μg m-3). Limonene was then introduced into the chamber and oxidised, with the formation of SOA seen as a growth in the size of oxidised organic seed particles from 150 to 325 nm mean diameter. The effect of the partitioning of limonene oxidation products onto the seed aerosol was assessed using aerosol mass spectrometry during the experiment and the percentage of m/z 44, an indicator of degree of oxidation, increased from around 5 to 8%. The hygroscopicity of the aerosol also changed, with the growth factor for 200 nm particles increasing from less than 1.05 to 1.25 at 90% RH. The detailed chemical composition of the limonene SOA could be extracted from the complex β-caryophyllene matrix using two-dimensional gas chromatography (GC×GC) and liquid chromatography coupled to mass spectrometry. High resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICR-MS) was used to determine exact molecular formulae of the seed and the limonene modified aerosol. The average O:C ratio was seen to increase from 0.32 to 0.37 after limonene oxidation products had condensed onto the organic seed.

Kinetics, Mechanism, and Secondary Organic Aerosol Yield of Aqueous Phase Photo-oxidation of α-Pinene Oxidation Products

The Journal of Physical Chemistry A ◽

10.1021/acs.jpca.5b06237 ◽

2015 ◽

Vol 120 (9) ◽

pp. 1395-1407 ◽

Cited By ~ 42

Author(s):

Dana Aljawhary ◽

Ran Zhao ◽

Alex K.Y. Lee ◽

Chen Wang ◽

Jonathan P.D. Abbatt

Keyword(s):

Aqueous Phase ◽

Organic Aerosol ◽

Oxidation Products ◽

Photo Oxidation

Secondary organic aerosol formation from in situ OH, O<sub>3</sub>, and NO<sub>3</sub> oxidation of ambient forest air in an oxidation flow reactor

10.5194/acp-2016-1080 ◽

2017 ◽

Cited By ~ 1

Author(s):

Brett B. Palm ◽

Pedro Campuzano-Jost ◽

Douglas A. Day ◽

Amber M. Ortega ◽

Juliane L. Fry ◽

...

Keyword(s):

Mass Loss ◽

Flow Reactor ◽

Ambient Air ◽

Organic Aerosol ◽

Oxidation Products ◽

Organic Nitrates ◽

Aerosol Formation ◽

Wide Range ◽

Synoptic Conditions

Abstract. Ambient pine forest air was oxidized by OH, O3, or NO3 radicals using an oxidation flow reactor (OFR) during the BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen–Rocky Mountain Biogenic Aerosol Study) campaign to study biogenic secondary organic aerosol (SOA) formation and organic aerosol (OA) aging. A wide range of equivalent atmospheric photochemical ages was sampled, from hours up to days (for O3 and NO3) or weeks (for OH). Ambient air processed by the OFR was typically sampled every 20–30 min, in order to determine how the availability of SOA precursor gases in ambient air changed with diurnal and synoptic conditions, for each of the three oxidants. More SOA was formed during nighttime than daytime for all three oxidants, indicating that SOA precursor concentrations were higher at night. At all times of day, OH oxidation led to approximately 4 times more SOA formation than either O3 or NO3 oxidation. This is likely because O3 and NO3 will only react with gases containing C=C bonds (e.g., terpenes) to form SOA, but won’t react appreciably with many of their oxidation products or any species in the gas phase that lacks a C=C bond (e.g., pinonic acid, alkanes). In contrast, OH can continue to react with compounds that lack C=C bonds to produce SOA. Closure was achieved between the amount of SOA formed from O3 and NO3 oxidation in the OFR and the SOA predicted to form from measured concentrations of ambient monoterpenes and sesquiterpenes using published chamber yields. This is in contrast to previous work at this site (Palm et al., 2016), which has shown that a source of SOA from semi- and intermediate-volatility organic compounds (S/IVOCs) 3.4 times larger than the source from measured VOCs is needed to explain the measured SOA formation from OH oxidation. This work suggests that those S/IVOCs typically do not contain C=C bonds. O3 and NO3 oxidation produced SOA with elemental O:C and H:C similar to the least oxidized OA observed in local ambient air, and neither oxidant led to net mass loss at the highest exposures, in contrast with OH oxidation. An OH exposure in the OFR equivalent to several hours of atmospheric aging also produced SOA with O:C and H:C values similar to ambient OA, while higher aging (days–weeks) led to formation of SOA with progressively higher O:C and lower H:C (and net mass loss at the highest exposures). NO3 oxidation led to the production of particulate organic nitrates (pRONO2), while OH and O3 oxidation (under low NO) did not, as expected. These measurements of SOA formation provide the first direct comparison of SOA formation potential and chemical evolution from OH, O3 and NO3 oxidation in the real atmosphere, and help to clarify the oxidation processes that lead to SOA formation from biogenic hydrocarbons.

Phase partitioning and volatility of secondary organic aerosol components formed from α-pinene ozonolysis and OH oxidation: the importance of accretion products and other low volatility compounds

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-4463-2015 ◽

2015 ◽

Vol 15 (4) ◽

pp. 4463-4494 ◽

Cited By ~ 6

Author(s):

F. D. Lopez-Hilfiker ◽

C. Mohr ◽

M. Ehn ◽

F. Rubach ◽

E. Kleist ◽

...

Keyword(s):

Organic Compounds ◽

Mass Spectrometer ◽

Organic Aerosol ◽

Oxidation Products ◽

Negative Ion ◽

Ionization Mass ◽

Particle Phase ◽

Vapor Pressures ◽

Aerosol Mass

Abstract. We measured a large suite of gas and particle phase multi-functional organic compounds with a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a high-resolution time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) developed at the University of Washington. The instrument was deployed on environmental simulation chambers to study monoterpene oxidation as a secondary organic aerosol (SOA) source. We focus here on results from experiments utilizing an ionization method most selective towards acids (acetate negative ion proton transfer), but our conclusions are based on more general physical and chemical properties of the SOA. Hundreds of compounds were observed in both gas and particle phases, the latter being detected upon temperature programmed thermal desorption of collected particles. Particulate organic compounds detected by the FIGAERO HR-ToF-CIMS are highly correlated with, and explain at least 25–50% of, the organic aerosol mass measured by an Aerodyne Aerosol Mass Spectrometer (AMS). Reproducible multi-modal structures in the thermograms for individual compounds of a given elemental composition reveal a significant SOA mass contribution from large molecular weight organics and/or oligomers (i.e. multi-phase accretion reaction products). Approximately 50% of the HR-ToF-CIMS particle phase mass is associated with compounds having effective vapor pressures 4 or more orders of magnitude lower than commonly measured monoterpene oxidation products. The relative importance of these accretion-type and other extremely low volatility products appears to vary with photochemical conditions. We present a desorption temperature based framework for apportionment of thermogram signals into volatility bins. The volatility-based apportionment greatly improves agreement between measured and modeled gas–particle partitioning for select major and minor components of the SOA, consistent with thermal decomposition during desorption causing the conversion of lower volatility components into the detected higher volatility compounds.