scholarly journals Optical Properties of Secondary Organic Aerosol Produced by Nitrate Radical Oxidation of Biogenic Volatile Organic Compounds

2021 ◽  
Author(s):  
Quanfu He ◽  
Sophie Tomaz ◽  
Chunlin Li ◽  
Ming Zhu ◽  
Daphne Meidan ◽  
...  
Keyword(s):  
Optical Properties ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Nitrate Radical ◽  
Biogenic Volatile Organic Compounds ◽  
Radical Oxidation ◽  
Volatile Organic

Optical Properties of Secondary Organic Aerosol from Nitrate Radical Oxidation of Biogenic Volatile Organic Compounds: The Role of Highly Oxygenated Organic Nitrates  

2020 ◽  
Author(s):  
Yinon Rudich ◽  
Quanfu He ◽  
Alexander Laskin ◽  
Steve Brown
Keyword(s):  
Optical Properties ◽  
Chemical Composition ◽  
High Resolution ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Organic Nitrates ◽  
Nitrate Radical ◽  
Biogenic Volatile Organic Compounds ◽  
Radical Oxidation ◽  
Volatile Organic

<p>Nitrate radical (NO<sub>3</sub>) oxidation of biogenic volatile organic compounds (BVOCs) represents one of the most important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. The functionalization process during this oxidation process leads to the formation of multifunctional compounds such as organic nitrates (ON). ON account for a significant fraction of total organic aerosols (OA) in ambient air, which influence atmospheric chemistry process, air quality, and climate through regional and global budgets for reactive nitrogen (particularly ON), ozone, and OA formation. Despite the significance of this process in atmospheric chemistry, the climatic effect of SOA from this process is undefined, largely due to a lack of knowledge about their optical properties with respect to their chemical composition. In this study, we generated SOA from NO<sub>3</sub> radical oxidation of a series BVOCs including isoprene, monoterpenes, and sesquiterpenes followed by photo-chemically aging in oxidation flow reactor (OFR/PAM). The chemical composition of the SOA was characterized online by high-resolution time-of-flight mass spectrometer (HR-Tof-AMS) and off-line by ultra-high-performance liquid chromatography (HPLC) coupled with photodiode array (PDA) detector coupled to a high-resolution Orbitrap mass spectrometer with a standard electrospray ionization (ESI) source (HPLC-PDA-HRMS). The UV-visible wavelength-resolved refractive index of the SOA, which is essential to understand their radiative forcing, was retrieved by measuring the light extinction using a novel broadband cavity-enhanced spectrometer (BBCES, 315-700 nm). We found that the SOA contain a large fraction of highly oxygenated ON, consisting of monomers and oligomers with single and multiple nitrate groups, which formed through bimolecular and unimolecular reactions. Strong absorption was detected in the UVA range which was attributed to the ON. The influence of the initial BVOCs/NO<sub>3</sub> ratio and the transition from nighttime oxidation to daytime aging on the SOA optical properties will be discussed. We will highlight the link between the SOA optical properties evolution and the chemical composition transformation with respect to the highly oxygenated ON formation and its atmospheric fate upon daytime photochemical aging.</p>

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 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...

scholarly journals Secondary organic aerosol enhanced by increasing atmospheric oxidizing capacity in Beijing–Tianjin–Hebei (BTH), China

2019 ◽  
Vol 19 (11) ◽  
pp. 7429-7443 ◽  
Author(s):  
Tian Feng ◽  
Shuyu Zhao ◽  
Naifang Bei ◽  
Jiarui Wu ◽  
Suixin Liu ◽  
...  
Keyword(s):  
Air Pollution ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Secondary Organic Aerosol ◽  
Action Plan ◽  
Spatial Relationship ◽  
Pollution Prevention ◽  
Organic Aerosol ◽  
Temporal Variations ◽  
Volatile Organic

Abstract. The implementation of the Air Pollution Prevention and Control Action Plan in China since 2013 has profoundly altered the ambient pollutants in the Beijing–Tianjin–Hebei (BTH) region. Here we show observations of substantially increased O3 concentrations (about 30 %) and a remarkable increase in the ratio of organic carbon (OC) to elemental carbon (EC) in BTH during the autumn from 2013 to 2015, revealing an enhancement in atmospheric oxidizing capacity (AOC) and secondary organic aerosol (SOA) formation. To explore the impacts of increasing AOC on the SOA formation, a severe air pollution episode from 3 to 8 October 2015 with high O3 and PM2.5 concentrations is simulated using the WRF-Chem model. The model performs reasonably well in simulating the spatial distributions of PM2.5 and O3 concentrations over BTH and the temporal variations in PM2.5, O3, NO2, OC, and EC concentrations in Beijing compared to measurements. Sensitivity studies show that the change in AOC substantially influences the SOA formation in BTH. A sensitivity case characterized by a 31 % O3 decrease (or 36 % OH decrease) reduces the SOA level by about 30 % and the SOA fraction in total organic aerosol by 17 % (from 0.52 to 0.43, dimensionless). Spatially, the SOA decrease caused by reduced AOC is ubiquitous in BTH, but the spatial relationship between SOA concentrations and the AOC is dependent on the SOA precursor distribution. Studies on SOA formation pathways further show that when the AOC is reduced, the SOA from oxidation and partitioning of semivolatile primary organic aerosol (POA) and co-emitted intermediate volatile organic compounds (IVOCs) decreases remarkably, followed by those from anthropogenic and biogenic volatile organic compounds (VOCs). Meanwhile, the SOA decrease in the irreversible uptake of glyoxal and methylglyoxal on the aerosol surfaces is negligible.

scholarly journals Nitrate radicals and biogenic volatile organic compounds: oxidation, mechanisms and organic aerosol

2016 ◽  
Author(s):  
N. L. Ng ◽  
S. S. Brown ◽  
A. T. Archibald ◽  
E. Atlas ◽  
R. C. Cohen ◽  
...  
Keyword(s):  
Air Quality ◽  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Atmospheric Chemistry ◽  
Climate Models ◽  
Large Body ◽  
Organic Aerosol ◽  
Organic Nitrate ◽  
Biogenic Volatile Organic Compounds ◽  
Volatile Organic

Abstract. Oxidation of biogenic volatile organic compounds (BVOC) by the nitrate radical (NO3) represents one of the important interactions between anthropogenic emissions related to combustion and natural emissions from the biosphere. This interaction has been recognized for more than three decades, during which time a large body of research has emerged from laboratory, field and modeling studies. NO3-BVOC reactions influence air quality, climate and visibility through regional and global budgets for reactive nitrogen (particularly organic nitrates), ozone and organic aerosol. Despite its long history of research and the significance of this topic in atmospheric chemistry, a number of important uncertainties remain. These include an incomplete understanding of the rates, mechanisms and organic aerosol yields for NO3-BVOC reactions, lack of constraints on the role of heterogeneous oxidative processes associated with the NO3 radical, the difficulty of characterizing the spatial distributions of BVOC and NO3 within the poorly mixed nocturnal atmosphere and the challenge of constructing appropriate boundary layer schemes and non-photochemical mechanisms for use in state-of-the-art chemical transport and chemistry-climate models. This review is the result of a workshop of the same title held at the Georgia Institute of Technology in June 2015. The first section summarizes the current literature on NO3-BVOC chemistry, with a particular focus on recent advances in instrumentation and models, and in organic nitrate and secondary organic aerosol (SOA) formation chemistry. Building on this current understanding, the second half of the review outlines impacts of NO3-BVOC chemistry on air quality and climate, and suggests critical research needs to better constrain this interaction to improve the predictive capabilities of atmospheric models.

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