Nitrate and secondary organic aerosol dominated particle light extinction in Beijing due to clean air action

Abstract. We present high-resolution atmospheric chemistry transport model (ACTM) simulations of secondary organic aerosol (SOA) formation over the UK for 2012. Our simulations include additional diesel-related intermediate volatility organic compound (IVOC) emissions derived directly from comprehensive field measurements at an urban background site in London during the 2012 Clean Air for London (ClearfLo) campaign. Our IVOC emissions are added proportionally to VOC emissions, as opposed to proportionally to primary organic aerosol (POA) as has been done by previous ACTM studies seeking to simulate the effects of these missing emissions. Modelled concentrations are evaluated against hourly and daily measurements of organic aerosol (OA) components derived from aerosol mass spectrometer (AMS) measurements also made during the ClearfLo campaign at three sites in the London area. Good hourly performance in comparison to the measurements was shown, giving confidence in the SOA prediction skill of the ACTM system used. According to the model simulations, diesel-related IVOCs can explain on average ~30% of the annual SOA in and around London. Furthermore, the 90-th percentile of modelled daily SOA concentrations for the whole year is 3.8 μg m−3 (more than 40% of which is produced from the missing diesel precursors), constituting a notable addition to total particulate matter. More measurements of these precursors (currently not included in official emissions inventories) is recommended. During the period of concurrent measurements, SOA concentrations at the Detling rural background location east of London were greater than at the central London location. The model shows that this was caused by an intense pollution plume with a strong gradient of imported SOA passing over the rural location. This demonstrates the value of modelling for supporting the interpretation of measurements taken at different sites or for short durations.

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Simulating secondary organic aerosol from missing diesel-related intermediate-volatility organic compound emissions during the Clean Air for London (ClearfLo) campaign

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-6453-2016 ◽

2016 ◽

Vol 16 (10) ◽

pp. 6453-6473 ◽

Cited By ~ 29

Author(s):

Riinu Ots ◽

Dominique E. Young ◽

Massimo Vieno ◽

Lu Xu ◽

Rachel E. Dunmore ◽

...

Keyword(s):

Organic Compound ◽

Secondary Organic Aerosol ◽

Transport Model ◽

Field Measurements ◽

Organic Aerosol ◽

Chemical Transport Model ◽

Total Particulate Matter ◽

Clean Air ◽

The Uk ◽

The Impact

Abstract. We present high-resolution (5 km  ×  5 km) atmospheric chemical transport model (ACTM) simulations of the impact of newly estimated traffic-related emissions on secondary organic aerosol (SOA) formation over the UK for 2012. Our simulations include additional diesel-related intermediate-volatility organic compound (IVOC) emissions derived directly from comprehensive field measurements at an urban background site in London during the 2012 Clean Air for London (ClearfLo) campaign. Our IVOC emissions are added proportionally to VOC emissions, as opposed to proportionally to primary organic aerosol (POA) as has been done by previous ACTM studies seeking to simulate the effects of these missing emissions. Modelled concentrations are evaluated against hourly and daily measurements of organic aerosol (OA) components derived from aerosol mass spectrometer (AMS) measurements also made during the ClearfLo campaign at three sites in the London area. According to the model simulations, diesel-related IVOCs can explain on average ∼  30 % of the annual SOA in and around London. Furthermore, the 90th percentile of modelled daily SOA concentrations for the whole year is 3.8 µg m−3, constituting a notable addition to total particulate matter. More measurements of these precursors (currently not included in official emissions inventories) is recommended. During the period of concurrent measurements, SOA concentrations at the Detling rural background location east of London were greater than at the central London location. The model shows that this was caused by an intense pollution plume with a strong gradient of imported SOA passing over the rural location. This demonstrates the value of modelling for supporting the interpretation of measurements taken at different sites or for short durations.

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Photodegradation of secondary organic aerosol generated from limonene oxidation by ozone studied with chemical ionization mass spectrometry

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-9-4727-2009 ◽

2009 ◽

Vol 9 (1) ◽

pp. 4727-4767

Author(s):

X. Pan ◽

J. S. Underwood ◽

J.-H. Xing ◽

S. A. Mang ◽

S. A. Nizkorodov

Keyword(s):

Mass Spectrometry ◽

Chemical Ionization ◽

Secondary Organic Aerosol ◽

Wavelength Dependence ◽

Organic Aerosol ◽

Ionization Mass Spectrometry ◽

Chemical Ionization Mass Spectrometry ◽

Ionization Mass ◽

Clean Air ◽

Irradiation Wavelength

Abstract. Photodegradation of secondary organic aerosol (SOA) prepared by ozone-initiated oxidation of D-limonene is studied with an action spectroscopy approach, which relies on detection of volatile photoproducts with chemical ionization mass-spectrometry as a function of the UV irradiation wavelength. Efficient photodegradation is observed for a broad range of ozone and D-limonene concentrations (0.1–300 ppm) used in the preparation of SOA. The observed photoproducts are dominated by oxygenated C1-C3 compounds such as methanol, formic acid, acetaldehyde, acetic acid, and acetone. The irradiation wavelength dependence of the combined yield of the photoproducts closely tracks the absorption spectrum of the SOA material suggesting that photodegradation is not limited to the UV wavelengths. Kinetic simulations suggest that RO2+HO2/RO2 reactions represent the dominant route to photochemically active carbonyl and peroxide species in the limonene SOA material. Similar photodegradation processes are likely to occur in realistic SOA produced by OH- or O3-initiated oxidation of biogenic volatile organic compounds in clean air.

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Insights into the O : C dependent mechanisms controlling the evaporation of α-pinene secondary organic aerosol particles

10.5194/acp-2018-1305 ◽

2019 ◽

Author(s):

Angela Buchholz ◽

Andrew T. Lambe ◽

Arttu Ylisirniö ◽

Zijun Li ◽

Olli-Pekka Tikkanen ◽

...

Keyword(s):

Flow Reactor ◽

Secondary Organic Aerosol ◽

Organic Aerosol ◽

Oxidation Products ◽

Particle Phase ◽

Volatile Organic ◽

Isothermal Evaporation ◽

Key Factor ◽

Clean Air ◽

Measured Particle

Abstract. The volatility of oxidation products of volatile organic compounds (VOCs) in the atmosphere is a key factor to determine if they partition into the particle phase contributing to secondary organic aerosol (SOA) mass. Thus, linking volatility and measured particle composition will provide insights into SOA formation and its fate in the atmosphere. We produced a-pinene SOA with three different oxidation levels (characterised by average oxygen to carbon ratio, O : C = 0.53, 0.69, and 0.96) in an oxidation flow reactor. We investigated the particle volatility by isothermal evaporation in clean air as a function of relative humidity (RH

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Photodegradation of secondary organic aerosol generated from limonene oxidation by ozone studied with chemical ionization mass spectrometry

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-3851-2009 ◽

2009 ◽

Vol 9 (12) ◽

pp. 3851-3865 ◽

Cited By ~ 35

Author(s):

X. Pan ◽

J. S. Underwood ◽

J.-H. Xing ◽

S. A. Mang ◽

S. A. Nizkorodov

Keyword(s):

Mass Spectrometry ◽

Chemical Ionization ◽

Secondary Organic Aerosol ◽

Wavelength Dependence ◽

Organic Aerosol ◽

Ionization Mass Spectrometry ◽

Chemical Ionization Mass Spectrometry ◽

Ionization Mass ◽

Clean Air ◽

Irradiation Wavelength

Abstract. Photodegradation of secondary organic aerosol (SOA) prepared by ozone-initiated oxidation of D-limonene is studied with an action spectroscopy approach, which relies on detection of volatile photoproducts with chemical ionization mass-spectrometry as a function of the UV irradiation wavelength. Efficient photodegradation is observed for a broad range of ozone (0.1–300 ppm) and D-limonene (0.02–3 ppm) concentrations used in the preparation of SOA. The observed photoproducts are dominated by oxygenated C1-C3 compounds such as methanol, formic acid, acetaldehyde, acetic acid, and acetone. The irradiation wavelength dependence of the combined yield of the photoproducts closely tracks the absorption spectrum of the SOA material suggesting that photodegradation is not limited to the UV wavelengths. Kinetic simulations suggest that RO2+HO2/RO2 reactions represent the dominant route to photochemically active carbonyl and peroxide species in the limonene SOA prepared in these experiments. Similar photodegradation processes are likely to occur in realistic SOA produced by OH- or O3-initiated oxidation of biogenic volatile organic compounds in clean air.

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Secondary organic aerosol formation from biomass burning emissions

10.5194/acp-2019-326 ◽

2019 ◽

Cited By ~ 2

Author(s):

Christopher Y. Lim ◽

David H. Hagan ◽

Matthew M. Coggon ◽

Abigail R. Koss ◽

Kanako Sekimoto ◽

...

Keyword(s):

Biomass Burning ◽

Secondary Organic Aerosol ◽

Total Concentration ◽

Organic Aerosol ◽

Oh Radicals ◽

Aerosol Formation ◽

Atmospheric Aging ◽

Aerosol Mass ◽

Photochemical Aging ◽

Organic Gases

Abstract. Biomass burning is an important source of aerosol and trace gases to the atmosphere, but how these emissions change chemically during their lifetimes is not fully understood. As part of the Fire Influence on Regional and Global Environments Experiment (FIREX 2016), we investigated the effect of photochemical aging on biomass burning organic aerosol (BBOA), with a focus on fuels from the western United States. Emissions were sampled into a small (150 L) environmental chamber and photochemically aged via the addition of ozone and irradiation by 254 nm light. While some fraction of species undergoes photolysis, the vast majority of aging occurs via reaction with OH radicals, with total OH exposures corresponding to the equivalent of up to 10 days of atmospheric oxidation. For all fuels burned, large and rapid changes are seen in the ensemble chemical composition of BBOA, as measured by an aerosol mass spectrometer (AMS). Secondary organic aerosol (SOA) formation is seen for all aging experiments and continues to grow with increasing OH exposure, but the magnitude of the SOA formation is highly variable between experiments. This variability can be explained well by a combination of experiment-to-experiment differences in OH exposure and the total concentration of non-methane organic gases (NMOGs) in the chamber before oxidation, measured by PTR-ToF-MS (r2 values from 0.64 to 0.83). From this relationship, we calculate the fraction of carbon from biomass burning NMOGs that is converted to SOA as a function of equivalent atmospheric aging time, with carbon yields ranging from 24 ± 4 % after 6 hours to 56 ± 9 % after 4 days.

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Aging of atmospheric aerosols and the role of iron in catalyzing brown carbon formation

Environmental Science: Atmospheres ◽

10.1039/d1ea00038a ◽

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...

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