Atmospheric Degradation Initiated by OH Radicals of the Potential Foam Expansion Agent, CF3(CF2)2CH═CH2 (HFC-1447fz): Kinetics and Formation of Gaseous Products and Secondary Organic Aerosols

2016 ◽  
Vol 50 (3) ◽  
pp. 1234-1242 ◽  
Author(s):  
Elena Jiménez ◽  
Sergio González ◽  
Mathieu Cazaunau ◽  
Hui Chen ◽  
Bernabé Ballesteros ◽  
...  
Keyword(s):  
Secondary Organic Aerosols ◽  
Organic Aerosols ◽  
Oh Radicals ◽  
Foam Expansion ◽  
Gaseous Products ◽  
Atmospheric Degradation

scholarly journals Studying volatility from composition, dilution, and heating measurements of secondary organic aerosols formed during <i>α</i>-pinene ozonolysis

2018 ◽  
Vol 18 (8) ◽  
pp. 5455-5466 ◽  
Author(s):  
Kei Sato ◽  
Yuji Fujitani ◽  
Satoshi Inomata ◽  
Yu Morino ◽  
Kiyoshi Tanabe ◽  
...  
Keyword(s):  
Secondary Organic Aerosols ◽  
Yield Curve ◽  
Volume Fraction ◽  
Organic Aerosols ◽  
Accommodation Coefficient ◽  
Oh Radicals ◽  
Ionization Mass ◽  
Mass Accommodation Coefficient ◽  
Kinetic Inhibition ◽  
Photochemical Aging

Abstract. Traditional yield curve analysis shows that semi-volatile organic compounds are a major component of secondary organic aerosols (SOAs). We investigated the volatility distribution of SOAs from α-pinene ozonolysis using positive electrospray ionization mass analysis and dilution- and heat-induced evaporation measurements. Laboratory chamber experiments were conducted on α-pinene ozonolysis, in the presence and absence of OH scavengers. Among these, we identified not only semi-volatile products, but also less volatile highly oxygenated molecules (HOMs) and dimers. Ozonolysis products were further exposed to OH radicals to check the effects of photochemical aging. HOMs were also formed during OH-initiated photochemical aging. Most HOMs that formed from ozonolysis and photochemical aging had 10 or fewer carbons. SOA particle evaporation after instantaneous dilution was measured at  < 1 and  ∼ 40 % relative humidity. The volume fraction remaining of SOAs decreased with time and the equilibration timescale was determined to be 24–46 min for SOA evaporation. The experimental results of the equilibration timescale can be explained when the mass accommodation coefficient is assumed to be 0.1, suggesting that the existence of low-volatility materials in SOAs, kinetic inhibition, or some combined effect may affect the equilibration timescale measured in this study.

scholarly journals Evaluation of the daytime tropospheric loss of 2-methylbutanal

2021 ◽  
Author(s):  
María Asensio ◽  
María Antiñolo ◽  
Sergio Blázquez ◽  
José Albaladejo ◽  
Elena Jiménez
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Degradation Products ◽  
Rate Coefficients ◽  
Oh Radicals ◽  
Phase Reaction ◽  
Gaseous Products ◽  
Flight Mass Spectrometry ◽  
Atmospheric Degradation ◽  
The Impact

Abstract. Saturated aldehydes, e.g. 2-methylbutanal (2MB, CH3CH2CH(CH3)C(O)H), are emitted into the atmosphere by several biogenic sources. The first step in the daytime atmospheric degradation of 2MB involves gas-phase reactions initiated by hydroxyl (OH) radicals, chlorine (Cl) atoms and/or sunlight. In this work, we report the rate coefficients for the gas-phase reaction of 2MB with OH (kOH) and Cl (kCl) together with the photolysis rate coefficient (J) in the ultraviolet solar actinic region in Valencia (Spain) at different times of the day. The temperature dependence of kOH was described in the 263–353 K range by the following Arrhenius expression: kOH(T)=(8.88±0.41)×10-12 exp[(331±14)/T] cm3 molecule-1 s-1. At 298 K, the reported kOH and kCl are (2.68±0.07)×10-11 cm3 molecule-1 s-1 and (2.16±0.16)×10-11 cm3 molecule-1 s-1. Identification and quantification of the gaseous products of the Cl-reaction and those from the photodissociation of 2MB were carried out in a smog chamber by different techniques (Fourier transform infrared spectroscopy, proton transfer time-of-flight mass spectrometry, and gas chromatography coupled to mass spectrometry). The formation and size distribution of secondary organic aerosols formed in the Cl-reaction was monitored by a fast mobility particle sizer spectrometer. A discussion on the relative importance of the first step in the daytime atmospheric degradation of 2MB is presented together with the impact of the degradation products in marine atmospheres.

scholarly journals Reactive oxygen species formed in aqueous mixtures of secondary organic aerosols and mineral dust influencing cloud chemistry and public health in the Anthropocene

2017 ◽  
Vol 200 ◽  
pp. 251-270 ◽  
Author(s):  
Haijie Tong ◽  
Pascale S. J. Lakey ◽  
Andrea M. Arangio ◽  
Joanna Socorro ◽  
Christopher J. Kampf ◽  
...  
Keyword(s):  
Public Health ◽  
Reactive Oxygen Species ◽  
Secondary Organic Aerosols ◽  
Mineral Dust ◽  
Organic Aerosols ◽  
Reactive Oxygen ◽  
Oh Radicals ◽  
Oxygen Species ◽  
Aqueous Mixtures ◽  
Cloud Chemistry

Mineral dust and secondary organic aerosols (SOA) account for a major fraction of atmospheric particulate matter, affecting climate, air quality and public health. How mineral dust interacts with SOA to influence cloud chemistry and public health, however, is not well understood. Here, we investigated the formation of reactive oxygen species (ROS), which are key species of atmospheric and physiological chemistry, in aqueous mixtures of SOA and mineral dust by applying electron paramagnetic resonance (EPR) spectrometry in combination with a spin-trapping technique, liquid chromatography-tandem mass spectrometry (LC-MS/MS), and a kinetic model. We found that substantial amounts of ROS including OH, superoxide as well as carbon- and oxygen-centred organic radicals can be formed in aqueous mixtures of isoprene, α-pinene, naphthalene SOA and various kinds of mineral dust (ripidolite, montmorillonite, kaolinite, palygorskite, and Saharan dust). The molar yields of total radicals were ∼0.02–0.5% at 295 K, which showed higher values at 310 K, upon 254 nm UV exposure, and under low pH (<3) conditions. ROS formation can be explained by the decomposition of organic hydroperoxides, which are a prominent fraction of SOA, through interactions with water and Fenton-like reactions with dissolved transition metal ions. Our findings imply that the chemical reactivity and aging of SOA particles can be enhanced upon interaction with mineral dust in deliquesced particles or cloud/fog droplets. SOA decomposition could be comparably important to the classical Fenton reaction of H2O2 with Fe2+ and that SOA can be the main source of OH radicals in aqueous droplets at low concentrations of H2O2 and Fe2+. In the human respiratory tract, the inhalation and deposition of SOA and mineral dust can also lead to the release of ROS, which may contribute to oxidative stress and play an important role in the adverse health effects of atmospheric aerosols in the Anthropocene.

scholarly journals Heterogeneous conversion of NO<sub>2</sub> on secondary organic aerosol surfaces: A possible source of nitrous acid (HONO) in the atmosphere?

2003 ◽  
Vol 3 (3) ◽  
pp. 469-474 ◽  
Author(s):  
R. Bröske ◽  
J. Kleffmann ◽  
P. Wiesen
Keyword(s):  
Nitrous Acid ◽  
Secondary Organic Aerosols ◽  
Organic Aerosols ◽  
Oh Radicals ◽  
Atmospheric Conditions ◽  
Alpha Pinene ◽  
Upper Limits ◽  
Uptake Coefficients ◽  
Heterogeneous Formation ◽  
Organic Particles

Abstract. The heterogeneous conversion of NO2 on different secondary organic aerosols (SOA) was investigated with the focus on a possible formation of nitrous acid (HONO). In one set of experiments different organic aerosols were produced in the reactions of O3 with alpha-pinene, limonene or catechol and OH radicals with toluene or limonene, respectively. The aerosols were sampled on filters and exposed to humidified NO2  mixtures under atmospheric conditions. The estimated upper limits for the uptake coefficients of NO2  and the reactive uptake coefficients NO2  -> HONO are in the range of 10-6 and 10-7, respectively. The integrated HONO formation for 1 h reaction time was <1013 cm-2 geometrical surface and <1017 g-1 particle mass. In a second set of experiments the conversion of NO2 into HONO in the presence of organic particles was carried out in an aerosol flow tube under atmospheric conditions. In this case the aerosols were produced in the reaction of O3 with beta-pinene, limonene or catechol, respectively. The upper limits for the reactive uptake coefficients NO2 -> HONO were in the range of 7 x 10-7 - 9 x 10-6. The results from the present study show that heterogeneous formation of nitrous acid on secondary organic aerosols (SOA) is unimportant for the atmosphere.

scholarly journals Lower than expected volatility of secondary organic aerosols formed during α-pinene ozonolysis

2017 ◽  
Author(s):  
Kei Sato ◽  
Yuji Fujitani ◽  
Satoshi Inomata ◽  
Yu Morino ◽  
Kiyoshi Tanabe ◽  
...  
Keyword(s):  
Secondary Organic Aerosols ◽  
Yield Curve ◽  
Organic Aerosols ◽  
Curve Analysis ◽  
Oh Radicals ◽  
Ionization Mass ◽  
Mass Analysis ◽  
Volatile Products ◽  
Volatile Organic ◽  
Photochemical Aging

Abstract. Traditional yield curve analysis shows that semi-volatile organic compounds are a major component of secondary organic aerosols (SOAs). We investigated the volatility distribution of SOAs from α-pinene ozonolysis using positive electrospray ionization mass analysis and dilution- and heat-induced evaporation measurements. Laboratory chamber experiments were conducted on α-pinene ozonolysis, in the presence and absence of OH scavengers. Among these, we identified not only semi-volatile products, but also less volatile highly oxygenated molecules (HOMs) and dimers. Ozonolysis products were further exposed to OH radicals to check the effects of photochemical aging. HOMs were also formed during OH-initiated photochemical aging. Most HOMs that formed from ozonolysis and photochemical aging had ten or less carbons. SOA particle evaporation after instantaneous dilution was measured at

scholarly journals Heterogeneous conversion of NO<sub>2</sub> on secondary organic aerosol surfaces: A possible source of nitrous acid (HONO) in the atmosphere?

2003 ◽  
Vol 3 (1) ◽  
pp. 597-613 ◽  
Author(s):  
R. Bröske ◽  
J. Kleffmann ◽  
P. Wiesen
Keyword(s):  
Nitrous Acid ◽  
Secondary Organic Aerosols ◽  
Organic Aerosols ◽  
Oh Radicals ◽  
Atmospheric Conditions ◽  
Flow Tube ◽  
Upper Limits ◽  
Uptake Coefficients ◽  
Heterogeneous Formation ◽  
Organic Particles

Abstract. The heterogeneous conversion of NO2 on different secondary organic aerosols (SOA) was investigated with the focus on a possible formation of nitrous acid (HONO). In one set of experiments different organic aerosols were produced in the reactions of O3 with α-pinene, limonene or catechol and OH radicals with toluene or limonene, respectively. The aerosols were sampled on filters and exposed to humidified NO2 mixtures under atmospheric conditions. The estimated upper limits for the uptake coefficients of NO2 and the reactive uptake coefficients NO2 →HONO are in the range of 10−6 and 10−7, respectively. The integrated HONO formation for 1 h reaction time was <1013 cm−2 geometrical surface and <1017 g−1 particle mass. In a second set of experiments the conversion of NO2 into HONO in the presence of organic particles was carried out in an aerosol flow tube under atmospheric conditions. In this case the aerosols were produced in the reaction of O3 with β-pinene, limonene or catechol, respectively. The upper limits for the reactive uptake coefficients NO2 \\rightarrow HONO were in the range of 7×10−7 −9×10−6. The results from the present study show that heterogeneous formation of nitrous acid on secondary organic aerosols (SOA) is unimportant for the atmosphere.

scholarly journals Large Discrepancy in the Formation of Secondary Organic Aerosols from Structurally Similar Monoterpenes

2021 ◽  
Vol 5 (3) ◽  
pp. 632-644
Author(s):  
Ditte Thomsen ◽  
Jonas Elm ◽  
Bernadette Rosati ◽  
Jane Tygesen Skønager ◽  
Merete Bilde ◽  
...  
Keyword(s):  
Secondary Organic Aerosols ◽  
Organic Aerosols

scholarly journals Aerosol chemical and optical properties over the Paris area within ESQUIF project

2006 ◽  
Vol 6 (11) ◽  
pp. 3257-3280 ◽  
Author(s):  
A. Hodzic ◽  
R. Vautard ◽  
P. Chazette ◽  
L. Menut ◽  
B. Bessagnet
Keyword(s):  
Optical Properties ◽  
Secondary Organic Aerosols ◽  
Organic Aerosols ◽  
Dust Particles ◽  
Aerosol Size Distribution ◽  
Aerosol Composition ◽  
Aerosol Mass ◽  
Coarse Mode ◽  
Paris Area ◽  
Flight Trajectories

Abstract. Aerosol chemical and optical properties are extensively investigated for the first time over the Paris Basin in July 2000 within the ESQUIF project. The measurement campaign offers an exceptional framework to evaluate the performances of the chemistry-transport model CHIMERE in simulating concentrations of gaseous and aerosol pollutants, as well as the aerosol-size distribution and composition in polluted urban environments against ground-based and airborne measurements. A detailed comparison of measured and simulated variables during the second half of July with particular focus on 19 and 31 pollution episodes reveals an overall good agreement for gas-species and aerosol components both at the ground level and along flight trajectories, and the absence of systematic biases in simulated meteorological variables such as wind speed, relative humidity and boundary layer height as computed by the MM5 model. A good consistency in ozone and NO concentrations demonstrates the ability of the model to reproduce the plume structure and location fairly well both on 19 and 31 July, despite an underestimation of the amplitude of ozone concentrations on 31 July. The spatial and vertical aerosol distributions are also examined by comparing simulated and observed lidar vertical profiles along flight trajectories on 31 July and confirm the model capacity to simulate the plume characteristics. The comparison of observed and modeled aerosol components in the southwest suburb of Paris during the second half of July indicates that the aerosol composition is rather correctly reproduced, although the total aerosol mass is underestimated by about 20%. The simulated Parisian aerosol is dominated by primary particulate matter that accounts for anthropogenic and biogenic primary particles (40%), and inorganic aerosol fraction (40%) including nitrate (8%), sulfate (22%) and ammonium (10%). The secondary organic aerosols (SOA) represent 12% of the total aerosol mass, while the mineral dust accounts for 8%. The comparison demonstrates the absence of systematic errors in the simulated sulfate, ammonium and nitrates total concentrations. However, for nitrates the observed partition between fine and coarse mode is not reproduced. In CHIMERE there is a clear lack of coarse-mode nitrates. This calls for additional parameterizations in order to account for the heterogeneous formation of nitrate onto dust particles. Larger discrepancies are obtained for the secondary organic aerosols due to both inconsistencies in the SOA formation processes in the model leading to an underestimation of their mass and large uncertainties in the determination of the measured aerosol organic fraction. The observed mass distribution of aerosols is not well reproduced, although no clear explanation can be given.

Atmospheric Degradation of CF3OCFCF2:  Kinetics and Mechanism of Its Reaction with OH Radicals and Cl Atoms

2000 ◽  
Vol 104 (13) ◽  
pp. 2925-2930 ◽  
Author(s):  
M. Mashino ◽  
M. Kawasaki ◽  
T. J. Wallington ◽  
M. D. Hurley
Keyword(s):  
Kinetics And Mechanism ◽  
Oh Radicals ◽  
Atmospheric Degradation ◽  
Cl Atoms
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