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

2008 ◽  
Vol 35 (2) ◽  
Author(s):  
Barbara Ervens ◽  
Annmarie G. Carlton ◽  
Barbara J. Turpin ◽  
Katye E. Altieri ◽  
Sonia M. Kreidenweis ◽  
...  
2017 ◽  
Author(s):  
Dongyu S. Wang ◽  
Lea Hildebrandt Ruiz

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.


2021 ◽  
Vol 7 (13) ◽  
pp. eabe2952
Author(s):  
Houssni Lamkaddam ◽  
Josef Dommen ◽  
Ananth Ranjithkumar ◽  
Hamish Gordon ◽  
Günther Wehrle ◽  
...  

Aerosols still present the largest uncertainty in estimating anthropogenic radiative forcing. Cloud processing is potentially important for secondary organic aerosol (SOA) formation, a major aerosol component: however, laboratory experiments fail to mimic this process under atmospherically relevant conditions. We developed a wetted-wall flow reactor to simulate aqueous-phase processing of isoprene oxidation products (iOP) in cloud droplets. We find that 50 to 70% (in moles) of iOP partition into the aqueous cloud phase, where they rapidly react with OH radicals, producing SOA with a molar yield of 0.45 after cloud droplet evaporation. Integrating our experimental results into a global model, we show that clouds effectively boost the amount of SOA. We conclude that, on a global scale, cloud processing of iOP produces 6.9 Tg of SOA per year or approximately 20% of the total biogenic SOA burden and is the main source of SOA in the mid-troposphere (4 to 6 km).


2009 ◽  
Vol 9 (2) ◽  
pp. 8857-8902 ◽  
Author(s):  
A. W. Rollins ◽  
A. Kiendler-Scharr ◽  
J. Fry ◽  
T. Brauers ◽  
S. S. Brown ◽  
...  

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.


2011 ◽  
Vol 11 (3) ◽  
pp. 1039-1050 ◽  
Author(s):  
N. H. Robinson ◽  
J. F. Hamilton ◽  
J. D. Allan ◽  
B. Langford ◽  
D. E. Oram ◽  
...  

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.


2009 ◽  
Vol 9 (18) ◽  
pp. 6685-6703 ◽  
Author(s):  
A. W. Rollins ◽  
A. Kiendler-Scharr ◽  
J. L. Fry ◽  
T. Brauers ◽  
S. S. Brown ◽  
...  

Abstract. Alkyl nitrates and secondary organic aerosol (SOA) produced during the oxidation of isoprene by nitrate radicals has been observed in the SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) chamber. A 16 h dark experiment was conducted with temperatures at 289–301 K, and maximum concentrations of 11 ppb isoprene, 62.4 ppb O3 and 31.1 ppb NOx. 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 molecule−1 cm3 s−1. At the low total organic aerosol concentration in the chamber (max=0.52 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 <0.7% while the further oxidation of the initial products leads to a yield of 14% (defined as ΔSOA/Δisoprene2x where Δisoprene2x is the mass of isoprene which reacted twice with NO3). The SOA yield of 14% is consistent with equilibrium partitioning of highly functionalized C5 products of isoprene oxidation.


2011 ◽  
Vol 11 (2) ◽  
pp. 893-909 ◽  
Author(s):  
F. Couvidat ◽  
C. Seigneur

Abstract. A new model for the formation of secondary organic aerosol (SOA) from isoprene was developed. This model uses surrogate molecular species (hydroxy-hydroperoxides, tetrols, methylglyceric acid, organic nitrates) to represent SOA formation. The development of this model used available experimental data on yields and molecular composition of SOA from isoprene and methacrolein oxidation. This model reproduces the amount of particles measured in smog chambers under both low-NOx and high-NOx conditions. Under low-NOx conditions, the model reproduces the transitional formation of hydroxy-hydroperoxides particles, which are photolyzed and lead to SOA mass decrease after reaching a maximum. Under high-NOx conditions, particles are assumed to be formed mostly from the photo-oxidation of a PAN-type molecule derived from methacrolein (MPAN). This model successfully reproduces the complex NOx-dependence of isoprene oxidation and suggests a possible yield increase under some high-NOx conditions. Experimental data correspond to dry conditions (RH < 10%). However, particles formed from isoprene are expected to be highly hydrophilic, and isoprene oxidation products would likely partition between an aqueous phase and the gas phase at high humidity in the atmosphere. The model was extended to take into account the hydrophilic properties of SOA, which are relevant under atmospheric conditions, and investigate the effect of particulate liquid water on SOA formation. An important increase in SOA mass was estimated for humid conditions due to the hydrophilic properties. Experiments under high relative humidity conditions should be conducted to confirm the results of this study, which have implications for SOA modeling.


2010 ◽  
Vol 10 (8) ◽  
pp. 20559-20605
Author(s):  
F. Couvidat ◽  
C. Seigneur

Abstract. A new model for the formation of secondary organic aerosol (SOA) from isoprene was developed. This model uses surrogate molecular species (hydroxy-hydroperoxides, tetrols, methylglyceric acid, organic nitrates) to represent SOA formation. The development of this model used available experimental data on yields and molecular composition of SOA from isoprene and methacrolein oxidation. This model reproduces the amount of particles measured in smog chambers under both low-NOx and high-NOx conditions. Under low-NOx conditions, the model reproduces the transitional formation of hydroxy-hydroperoxides particles, which are photolyzed and lead to SOA mass decrease after reaching a maximum. Under high-NOx conditions, particles are assumed to be formed mostly from the photo-oxidation of a PAN-type molecule derived from methacrolein (MPAN). This model successfully reproduces the complex NOx-dependence of isoprene oxidation and suggests a possible yield increase under some high-NOx conditions. Experimental data correspond to dry conditions (RH<10%). However, particles formed from isoprene are expected to be highly hydrophilic, and isoprene oxidation products would likely partition between an aqueous phase and the gas phase at high humidity in the atmosphere. The model was extended to take into account the hydrophilic properties of SOA, which are relevant under atmospheric conditions, and investigate the effect of particulate liquid water on SOA formation. An important increase in SOA mass was estimated for atmospheric conditions due to the hydrophilic properties. Experiments should be conducted to confirm the results of this study, which have implications for SOA modeling.


2010 ◽  
Vol 10 (11) ◽  
pp. 25545-25576 ◽  
Author(s):  
N. H. Robinson ◽  
J. F. Hamilton ◽  
J. D. Allan ◽  
B. Langford ◽  
D. E. Oram ◽  
...  

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.


2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
Tatu Anttila ◽  
Baerbel Langmann ◽  
Saji Varghese ◽  
Colin O'Dowd

Secondary organic aerosol (SOA) formation through isoprene oxidation was investigated with the regional-scale climate model REMOTE. The applied modeling scheme includes a treatment for marine primary organic aerosol emissions, aerosol microphysics, and SOA formation through the gas/particle partitioning of semivolatile, water-soluble oxidation products. The focus was on SOA formation taking place over the North-East Atlantic during a period of high biological activity. Isoprene SOA concentrations were up to ~5 ngm−3over North Atlantic in the base case model runs, and isoprene oxidation made a negligible contribution to the marine organic aerosol (OA) mass. In particular, isoprene SOA did not account for the observed water-soluble organic carbon (WSOC) concentrations over North Atlantic. The performed model calculations, together with results from recent field measurements, imply a missing source of SOA over remote marine areas unless the isoprene oxidation products are considerably less volatile than the current knowledge indicates.


2020 ◽  
Vol 20 (10) ◽  
pp. 5995-6014 ◽  
Author(s):  
Camille Mouchel-Vallon ◽  
Julia Lee-Taylor ◽  
Alma Hodzic ◽  
Paulo Artaxo ◽  
Bernard Aumont ◽  
...  

Abstract. The GoAmazon 2014/5 field campaign took place in Manaus, Brazil, and allowed the investigation of the interaction between background-level biogenic air masses and anthropogenic plumes. We present in this work a box model built to simulate the impact of urban chemistry on biogenic secondary organic aerosol (SOA) formation and composition. An organic chemistry mechanism is generated with the Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) to simulate the explicit oxidation of biogenic and anthropogenic compounds. A parameterization is also included to account for the reactive uptake of isoprene oxidation products on aqueous particles. The biogenic emissions estimated from existing emission inventories had to be reduced to match measurements. The model is able to reproduce ozone and NOx for clean and polluted situations. The explicit model is able to reproduce background case SOA mass concentrations but does not capture the enhancement observed in the urban plume. The oxidation of biogenic compounds is the major contributor to SOA mass. A volatility basis set (VBS) parameterization applied to the same cases obtains better results than GECKO-A for predicting SOA mass in the box model. The explicit mechanism may be missing SOA-formation processes related to the oxidation of monoterpenes that could be implicitly accounted for in the VBS parameterization.


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