scholarly journals Modeling the meteorological and chemical effects of secondary organic aerosols during an EUCAARI campaign

2013 ◽  
Vol 13 (2) ◽  
pp. 625-645 ◽  
Author(s):  
E. Athanasopoulou ◽  
H. Vogel ◽  
B. Vogel ◽  
A. P. Tsimpidi ◽  
S. N. Pandis ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Organic Aerosol ◽  
Atmospheric Model ◽  
Basis Set ◽  
High Temporal Resolution ◽  
Aerosol Mass Spectrometer ◽  
Spatially Correlated ◽  
Aerosol Mass ◽  
Inorganic Species ◽  
The Impact

Abstract. A volatility basis set (VBS) approach for the simulation of secondary organic aerosol (SOA) formation is incorporated in the online coupled atmospheric model system COSMO-ART and applied over Europe during the EUCAARI May 2008 campaign. Organic aerosol performance is improved when compared to the default SOA module of COSMO-ART (SORGAM) against high temporal resolution aerosol mass spectrometer ground measurements. The impact of SOA on the overall radiative budget was investigated. The mean direct surface radiative cooling averaged over Europe is −1.2 W m−2, representing approximately 20% of the total effect of aerosols on the radiative budget. However, responses are not spatially correlated with the radiative forcing, due to the nonlinear interactions among changes in particle chemical composition, water content, size distribution and cloud cover. These interactions initiated~by the effect of SOA on radiation are found to result even in a positive forcing in specific areas. Further model experiments showed that the availability of nitrogen oxides slightly affects SOA production, but that the aging rate constant used in the VBS approximation and boundary concentrations assumed in the model should be carefully selected. The aging of SOA is found to reduce hourly nitrate levels by up to 30%, while the condensation of inorganic species upon pre-existing, SOA-rich particles results in a monthly average increase of 5% in sulfate and ammonium formation in the accumulation mode.

scholarly journals Modeling meteorological and chemical effects of secondary organic aerosol during an EUCAARI campaign

2012 ◽  
Vol 12 (8) ◽  
pp. 21815-21865
Author(s):  
E. Athanasopoulou ◽  
H. Vogel ◽  
B. Vogel ◽  
A. Tsimpidi ◽  
S. N. Pandis ◽  
...  
Keyword(s):  
Cloud Cover ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Atmospheric Model ◽  
Basis Set ◽  
High Time Resolution ◽  
Aerosol Mass Spectrometer ◽  
Spatially Correlated ◽  
Aerosol Mass ◽  
Aerosol Effect

Abstract. A Volatility Basis Set (VBS) approach for Secondary Organic Aerosol (SOA) formation is incorporated in the online coupled atmospheric model system COSMO-ART and applied over Europe during the EUCAARI May 2008 campaign. Organic Aerosol (OA) performance is improved when compared to the default SOA module of COSMO-ART (SORGAM) against high time resolution Aerosol Mass Spectrometer (AMS) ground measurements. This allows the investigation of SOA impact upon the radiative budget. The mean direct surface radiative cooling averaged over Europe is −1.2 W m−2 and contributes by about 20% to the total aerosol effect. Nevertheless, responses are not spatially correlated with the forcing, due to the nonlinear interactions among changes in particle chemical composition, water content, size distribution and cloud cover. These interactions initiated~by~the effect of SOA on radiation result even in a positive forcing over a limited surface and mostly where the net effect of interactions on the cloud cover is negative. Further model experiments showed that nitrogen oxides availability slightly affects SOA production, but the aging rate constant within the VBS approximation and the boundary concentrations assumed in the model should be carefully selected. SOA aging is found to reduce hourly nitrate levels up to 30%, while the condensation upon pre-existing, SOA-rich particles result in a monthly average increase of 5% in sulfate and ammonium formation in the accumulation mode.

scholarly journals Formation of secondary organic aerosol coating on black carbon particles near vehicular emissions

2017 ◽  
Author(s):  
Alex K. Y. Lee ◽  
Chia-Li Chen ◽  
Jun Liu ◽  
Derek J. Price ◽  
Raghu Betha ◽  
...  
Keyword(s):  
Black Carbon ◽  
Mass Spectrometer ◽  
Secondary Organic Aerosol ◽  
Spectral Characteristics ◽  
Organic Aerosol ◽  
Vehicular Emissions ◽  
Aerosol Mass Spectrometer ◽  
Diurnal Cycles ◽  
Aerosol Mass ◽  
Inorganic Species

Abstract. Black carbon (BC) emitted from incomplete combustion can result in significant impacts on air quality and climate. Understanding the mixing state of ambient BC and the chemical characteristics of its associated coatings are particularly important to evaluate BC fate and environmental impacts. In this study, we investigate the formation of organic coatings on BC particles in an urban environment (Fontana, California) under hot and dry conditions using a Soot-Particle Aerosol Mass Spectrometer (SP-AMS). The SP-AMS was operated in a configuration that can detect refractory BC (rBC) particles and their coatings exclusively. Using the −log(NOx/NOy) ratio as a proxy for photochemical age of air masses, substantial formation of secondary organic aerosol (SOA) coatings on rBC particles was observed due to active photochemistry in the afternoon, whereas primary organic aerosol (POA) components were strongly associated with rBC from fresh vehicular missions in the morning rush hours. There is also evidence that cooking related organic aerosols were externally mixed from rBC. Positive matrix factorization and elemental analysis illustrate that most of the observed SOA coatings were freshly formed, providing an opportunity to examine SOA coating formation on rBC near vehicular emissions. Approximately 7–20 wt % of secondary organic and inorganic species were estimated to be internally mixed with rBC on average, implying that rBC is unlikely the major condensation sinks of SOA in this study. Diurnal cycles of oxygenated organic aerosol (OOA) observed by a co-located standard high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-MS) correlated well with that of SOA coatings on rBC, but their mass spectral characteristics were different from each other. Our results suggest that at least a portion of SOA materials condensed on rBC surface were chemically different from OOA particles that were externally mixed with rBC, although they are both generated from local photochemistry.

scholarly journals Volatility of organic aerosol and its components in the megacity of Paris

2016 ◽  
Vol 16 (4) ◽  
pp. 2013-2023 ◽  
Author(s):  
Andrea Paciga ◽  
Eleni Karnezi ◽  
Evangelia Kostenidou ◽  
Lea Hildebrandt ◽  
Magda Psichoudaki ◽  
...  
Keyword(s):  
Organic Aerosol ◽  
Basis Set ◽  
Transfer Model ◽  
Collaborative Project ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Combining Data ◽  
Wide Range ◽  
Order Of Magnitude ◽  
Effective Saturation

Abstract. Using a mass transfer model and the volatility basis set, we estimate the volatility distribution for the organic aerosol (OA) components during summer and winter in Paris, France as part of the collaborative project MEGAPOLI. The concentrations of the OA components as a function of temperature were measured combining data from a thermodenuder and an aerosol mass spectrometer (AMS) with Positive Matrix Factorization (PMF) analysis. The hydrocarbon-like organic aerosol (HOA) had similar volatility distributions for the summer and winter campaigns with half of the material in the saturation concentration bin of 10 µg m−3 and another 35–40 % consisting of low and extremely low volatility organic compounds (LVOCs with effective saturation concentrations C* of 10−3–0.1 µg m−3 and ELVOCs C* less or equal than 10−4 µg m−3, respectively). The winter cooking OA (COA) was more than an order of magnitude less volatile than the summer COA. The low-volatility oxygenated OA (LV-OOA) factor detected in the summer had the lowest volatility of all the derived factors and consisted almost exclusively of ELVOCs. The volatility for the semi-volatile oxygenated OA (SV-OOA) was significantly higher than that of the LV-OOA, containing both semi-volatile organic components (SVOCs with C* in the 1–100 µg m−3 range) and LVOCs. The oxygenated OA (OOA) factor in winter consisted of SVOCs (45 %), LVOCs (25 %) and ELVOCs (30 %). The volatility of marine OA (MOA) was higher than that of the other factors containing around 60 % SVOCs. The biomass burning OA (BBOA) factor contained components with a wide range of volatilities with significant contributions from both SVOCs (50 %) and LVOCs (30 %). Finally, combining the bulk average O : C ratios and volatility distributions of the various factors, our results are placed into the two-dimensional volatility basis set (2D-VBS) framework. The OA factors cover a broad spectrum of volatilities with no direct link between the average volatility and average O : C of the OA components.

scholarly journals Factor analysis of combined organic and inorganic aerosol mass spectra from high resolution aerosol mass spectrometer measurements

2012 ◽  
Vol 12 (18) ◽  
pp. 8537-8551 ◽  
Author(s):  
Y. L. Sun ◽  
Q. Zhang ◽  
J. J. Schwab ◽  
T. Yang ◽  
N. L. Ng ◽  
...  
Keyword(s):  
High Resolution ◽  
Ammonium Nitrate ◽  
Mass Spectrometer ◽  
Mass Spectra ◽  
Organic Aerosol ◽  
Organic Nitrates ◽  
Spectral Matrix ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Inorganic Species

Abstract. Positive matrix factorization (PMF) was applied to the merged high resolution mass spectra of organic and inorganic aerosols from aerosol mass spectrometer (AMS) measurements to investigate the sources and evolution processes of submicron aerosols in New York City in summer 2009. This new approach is able to study the distribution of organic and inorganic species in different types of aerosols, the acidity of organic aerosol (OA) factors, and the fragment ion patterns related to photochemical processing. In this study, PMF analysis of the unified AMS spectral matrix resolved 8 factors. The hydrocarbon-like OA (HOA) and cooking OA (COA) factors contain negligible amounts of inorganic species. The two factors that are primarily ammonium sulfate (SO4-OA) and ammonium nitrate (NO3-OA), respectively, are overall neutralized. Among all OA factors the organic fraction of SO4-OA shows the highest degree of oxidation (O/C = 0.69). Two semi-volatile oxygenated OA (OOA) factors, i.e., a less oxidized (LO-OOA) and a more oxidized (MO-OOA), were also identified. MO-OOA represents local photochemical products with a diurnal profile exhibiting a pronounced noon peak, consistent with those of formaldehyde (HCHO) and Ox(= O3 + NO2). The NO+/NO2+ ion ratio in MO-OOA is much higher than that in NO3-OA and in pure ammonium nitrate, indicating the formation of organic nitrates. The nitrogen-enriched OA (NOA) factor contains ~25% of acidic inorganic salts, suggesting the formation of secondary OA via acid-base reactions of amines. The size distributions of OA factors derived from the size-resolved mass spectra show distinct diurnal evolving behaviors but overall a progressing evolution from smaller to larger particle mode as the oxidation degree of OA increases. Our results demonstrate that PMF analysis of the unified aerosol mass spectral matrix which contains both inorganic and organic aerosol signals may enable the deconvolution of more OA factors and gain more insights into the sources, processes, and chemical characteristics of OA in the atmosphere.

scholarly journals Formation of secondary organic aerosol coating on black carbon particles near vehicular emissions

2017 ◽  
Vol 17 (24) ◽  
pp. 15055-15067 ◽  
Author(s):  
Alex K. Y. Lee ◽  
Chia-Li Chen ◽  
Jun Liu ◽  
Derek J. Price ◽  
Raghu Betha ◽  
...  
Keyword(s):  
Black Carbon ◽  
Mass Spectrometer ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Vehicular Emissions ◽  
Aerosol Mass Spectrometer ◽  
Carbon Particles ◽  
Aerosol Mass ◽  
Inorganic Species ◽  
Dry Conditions

Abstract. Black carbon (BC) emitted from incomplete combustion can result in significant impacts on air quality and climate. Understanding the mixing state of ambient BC and the chemical characteristics of its associated coatings is particularly important to evaluate BC fate and environmental impacts. In this study, we investigate the formation of organic coatings on BC particles in an urban environment (Fontana, California) under hot and dry conditions using a soot-particle aerosol mass spectrometer (SP-AMS). The SP-AMS was operated in a configuration that can exclusively detect refractory BC (rBC) particles and their coatings. Using the −log(NOx ∕ NOy) ratio as a proxy for photochemical age of air masses, substantial formation of secondary organic aerosol (SOA) coatings on rBC particles was observed due to active photochemistry in the afternoon, whereas primary organic aerosol (POA) components were strongly associated with rBC from fresh vehicular emissions in the morning rush hours. There is also evidence that cooking-related organic aerosols were externally mixed from rBC. Positive matrix factorization and elemental analysis illustrate that most of the observed SOA coatings were freshly formed, providing an opportunity to examine SOA coating formation on rBCs near vehicular emissions. Approximately 7–20 wt % of secondary organic and inorganic species were estimated to be internally mixed with rBC on average, implying that rBC is unlikely the major condensation sink of SOA in this study. Comparison of our results to a co-located standard high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) measurement suggests that at least a portion of SOA materials condensed on rBC surfaces were chemically different from oxygenated organic aerosol (OOA) particles that were externally mixed with rBC, although they could both be generated from local photochemistry.

scholarly journals Single particle characterization using the soot particle aerosol mass spectrometer (SP-AMS)

2014 ◽  
Vol 14 (10) ◽  
pp. 15323-15361 ◽  
Author(s):  
A. K. Y. Lee ◽  
M. D. Willis ◽  
R. M. Healy ◽  
T. B. Onasch ◽  
J. P. D. Abbatt
Keyword(s):  
Mass Spectrometer ◽  
Single Particle ◽  
Soot Particle ◽  
Organic Aerosol ◽  
Anthropogenic Sources ◽  
Mixing State ◽  
Aerosol Mass Spectrometer ◽  
Mass Spectral ◽  
Aerosol Mass ◽  
The Impact

Abstract. Understanding the impact of atmospheric black carbon (BC) containing particles on human health and radiative forcing requires knowledge of the mixing state of BC, including the characteristics of the materials with which it is internally mixed. In this study, we demonstrate for the first time the capabilities of the Aerodyne Soot-Particle Aerosol Mass Spectrometer equipped with a light scattering module (LS-SP-AMS) to examine the mixing state of refractory BC (rBC) and other aerosol components in an urban environment (downtown Toronto). K-means clustering analysis was used to classify single particle mass spectra into chemically distinct groups. One resultant cluster is dominated by rBC mass spectral signals (C1+ to C5+) while the organic signals fall into a few major clusters, identified as hydrocarbon-like organic aerosol (HOA), oxygenated organic aerosol (OOA), and cooking emission organic aerosol (COA). A nearly external mixing is observed with small BC particles only thinly coated by HOA (∼28% by mass on average), while over 90% of the HOA-rich particles did not contain detectable amounts of rBC. Most of the particles classified into other inorganic and organic clusters were not significantly associated with BC. The single particle results also suggest that HOA and COA emitted from anthropogenic sources were likely major contributors to organic-rich particles with low to mid-range aerodynamic diameter (dva). The similar temporal profiles and mass spectral features of the organic clusters and the factors from a positive matrix factorization (PMF) analysis of the ensemble aerosol dataset validate the conventional interpretation of the PMF results.

scholarly journals Volatility of organic aerosol and its components in the Megacity of Paris

2015 ◽  
Vol 15 (16) ◽  
pp. 22263-22289 ◽  
Author(s):  
A. Paciga ◽  
E. Karnezi ◽  
E. Kostenidou ◽  
L. Hildebrandt ◽  
M. Psichoudaki ◽  
...  
Keyword(s):  
Organic Aerosol ◽  
Basis Set ◽  
Transfer Model ◽  
Collaborative Project ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Combining Data ◽  
Wide Range ◽  
Volatile Organic ◽  
Order Of Magnitude

Abstract. Using a mass transfer model and the volatility basis set, we estimate the volatility distribution for the organic aerosol (OA) components during summer and winter in Paris, France as part of the collaborative project MEGAPOLI. The concentrations of the OA components as a function of temperature were measured combining data from a thermodenuder and an aerosol mass spectrometer (AMS) with Positive Matrix Factorization (PMF) analysis. The hydrocarbon-like organic aerosol (HOA) had similar volatility distributions for the summer and winter campaigns with half of the material in the saturation concentration bin of 10 μg m−3 and another 35–40 % consisting of low and extremely low volatility organic compounds (LVOCs and ELVOCs, respectively). The winter cooking OA (COA) was more than an order of magnitude less volatile than the summer COA. The low volatility oxygenated OA (LV-OOA) factor detected in the summer had the lowest volatility of all the derived factors and consisted almost exclusively of ELVOCs. The volatility for the semi-volatile oxygenated OA (SV-OOA) was significantly higher than that of the LV-OOA, containing both semi-volatile organic components (SVOCs) and LVOCs. The oxygenated OA (OOA) factor in winter consisted of SVOCs (45 %), LVOCs (25 %) and ELVOCs (30 %). The volatility of marine OA (MOA) was higher than that of the other factors containing around 60 % SVOCs. The biomass burning OA (BBOA) factor contained components with a wide range of volatilities with significant contributions from both SVOCs (50 %) and LVOCs (30 %). Finally, combining the O : C ratio and volatility distributions of the various factors, we incorporated our results into the two-dimensional volatility basis set (2D-VBS). Our results show that the factors cover a broad spectrum of volatilities with no direct link between the average volatility and average O : C of the OA components. Agreement between our findings and previous publications is encouraging for our understanding of the evolution of atmospheric OA.

scholarly journals Physicochemical properties and origin of organic groups detected in boreal forest using an aerosol mass spectrometer

2010 ◽  
Vol 10 (4) ◽  
pp. 2063-2077 ◽  
Author(s):  
T. Raatikainen ◽  
P. Vaattovaara ◽  
P. Tiitta ◽  
P. Miettinen ◽  
J. Rautiainen ◽  
...  
Keyword(s):  
Growth Factors ◽  
Mass Spectrometer ◽  
Organic Aerosol ◽  
Submicron Particles ◽  
Hygroscopic Growth ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Hygroscopic Properties ◽  
Inorganic Species ◽  
Wide Range

Abstract. An Aerodyne quadrupole aerosol mass spectrometer (Q-AMS) was deployed in Hyytiälä, a forested rural measurement site in southern Finland, during a 2-week measurement campaign in spring 2005. Q-AMS measures mass concentrations of non-refractory species including sulphate, nitrate, ammonium and organics from submicron particles. A positive matrix factorization method was used in identifying two oxygenated organic aerosol (OOA) groups from the measured total organic mass. The properties of these groups were estimated from their diurnal concentration cycles and correlations with additional data such as air mass history, particle number size distributions, hygroscopic and ethanol growth factors and particle volatility. It was found that the aged and highly oxidized background organic aerosol (OOA1 or LV-OOA) species have a wide range of hygroscopic growth factors and volatilization temperatures, but on the average OOA1 is the less volatile and more hygroscopic organic group. Hygroscopic properties and volatilities of the OOA1 species are correlated so that the less volatile species have higher hygroscopic growth factors. The other, less oxidized organic aerosol group (OOA2 or SV-OOA) is more volatile and non-hygroscopic. Trajectory analysis showed that OOA1 and the inorganic species are mainly long-range transported anthropogenic pollutions. OOA2 species and its precursor gases have short atmospheric life times, so they are from local sources. These results span the range of previous observations of oxygen content, volatility and hygroscopic growth factor, simultaneously coupling all three measurements for the first time.

scholarly journals Limited effect of anthropogenic nitrogen oxides on Secondary Organic Aerosol formation

2015 ◽  
Vol 15 (16) ◽  
pp. 23231-23277
Author(s):  
Y. Zheng ◽  
N. Unger ◽  
A. Hodzic ◽  
L. Emmons ◽  
C. Knote ◽  
...  
Keyword(s):  
Nitrogen Oxides ◽  
Secondary Organic Aerosol ◽  
Critical Role ◽  
Organic Aerosol ◽  
Atmospheric Model ◽  
Basis Set ◽  
Aerosol Formation ◽  
Aerosol Mass ◽  
Anthropogenic Nitrogen ◽  
Southeast Us

Abstract. Globally, secondary organic aerosol (SOA) is mostly formed from emissions of biogenic volatile organic compounds (VOCs) by vegetation, but can be modified by human activities as demonstrated in recent research. Specifically, nitrogen oxides (NOx = NO + NO2) have been shown to play a critical role in the chemical formation of low volatility compounds. We have updated the SOA scheme in the global NCAR Community Atmospheric Model version 4 with chemistry (CAM4-chem) by implementing a 4-product Volatility Basis Set (VBS) scheme, including NOx-dependent SOA yields and aging parameterizations. The predicted organic aerosol amounts capture both the magnitude and distribution of US surface annual mean measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network by 50 %, and the simulated vertical profiles are within a factor of two compared to Aerosol Mass Spectrometer (AMS) measurements from 13 aircraft-based field campaigns across different region and seasons. We then perform sensitivity experiments to examine how the SOA loading responds to a 50 % reduction in anthropogenic nitric oxide (NO) emissions in different regions. We find limited SOA reductions of 0.9 to 5.6, 6.4 to 12.0 and 0.9 to 2.8 % for global, the southeast US and the Amazon NOx perturbations, respectively. The fact that SOA formation is almost unaffected by changes in NOx can be largely attributed to buffering in chemical pathways (low- and high-NOx pathways, O3 versus NO3-initiated oxidation) and to offsetting tendencies in the biogenic versus anthropogenic SOA responses.

scholarly journals Limited effect of anthropogenic nitrogen oxides on secondary organic aerosol formation

2015 ◽  
Vol 15 (23) ◽  
pp. 13487-13506 ◽  
Author(s):  
Y. Zheng ◽  
N. Unger ◽  
A. Hodzic ◽  
L. Emmons ◽  
C. Knote ◽  
...  
Keyword(s):  
Nitrogen Oxides ◽  
Secondary Organic Aerosol ◽  
Critical Role ◽  
Organic Aerosol ◽  
Atmospheric Model ◽  
Basis Set ◽  
Aerosol Formation ◽  
Aerosol Mass ◽  
Anthropogenic Nitrogen ◽  
Southeast Us

Abstract. Globally, secondary organic aerosol (SOA) is mostly formed from emissions of biogenic volatile organic compounds (VOCs) by vegetation, but it can be modified by human activities as demonstrated in recent research. Specifically, nitrogen oxides (NOx = NO + NO2) have been shown to play a critical role in the chemical formation of low volatility compounds. We have updated the SOA scheme in the global NCAR (National Center for Atmospheric Research) Community Atmospheric Model version 4 with chemistry (CAM4-chem) by implementing a 4-product volatility basis set (VBS) scheme, including NOx-dependent SOA yields and aging parameterizations. Small differences are found for the no-aging VBS and 2-product schemes; large increases in SOA production and the SOA-to-OA ratio are found for the aging scheme. The predicted organic aerosol amounts capture both the magnitude and distribution of US surface annual mean measurements from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network by 50 %, and the simulated vertical profiles are within a factor of 2 compared to aerosol mass spectrometer (AMS) measurements from 13 aircraft-based field campaigns across different regions and seasons. We then perform sensitivity experiments to examine how the SOA loading responds to a 50 % reduction in anthropogenic nitric oxide (NO) emissions in different regions. We find limited SOA reductions of 0.9–5.6, 6.4–12.0 and 0.9–2.8 % for global, southeast US and Amazon NOx perturbations, respectively. The fact that SOA formation is almost unaffected by changes in NOx can be largely attributed to a limited shift in chemical regime, to buffering in chemical pathways (low- and high-NOx pathways, O3 versus NO3-initiated oxidation) and to offsetting tendencies in the biogenic versus anthropogenic SOA responses.

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