scholarly journals Sources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris

2012 ◽  
Vol 12 (4) ◽  
pp. 1681-1700 ◽  
Author(s):  
R. M. Healy ◽  
J. Sciare ◽  
L. Poulain ◽  
K. Kamili ◽  
M. Merkel ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Biomass Burning ◽  
Single Particle ◽  
Mass Concentration ◽  
Elemental Carbon ◽  
Fossil Fuel ◽  
Time Of Flight ◽  
Particle Mass ◽  
Mass Size ◽  
Mass Concentrations

Abstract. An Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS) was deployed to investigate the size-resolved chemical composition of single particles at an urban background site in Paris, France, as part of the MEGAPOLI winter campaign in January/February 2010. ATOFMS particle counts were scaled to match coincident Twin Differential Mobility Particle Sizer (TDMPS) data in order to generate hourly size-resolved mass concentrations for the single particle classes observed. The total scaled ATOFMS particle mass concentration in the size range 150–1067 nm was found to agree very well with the sum of concurrent High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and Multi-Angle Absorption Photometer (MAAP) mass concentration measurements of organic carbon (OC), inorganic ions and black carbon (BC) (R2 = 0.91). Clustering analysis of the ATOFMS single particle mass spectra allowed the separation of elemental carbon (EC) particles into four classes: (i) EC attributed to biomass burning (ECbiomass), (ii) EC attributed to traffic (ECtraffic), (iii) EC internally mixed with OC and ammonium sulfate (ECOCSOx), and (iv) EC internally mixed with OC and ammonium nitrate (ECOCNOx). Average hourly mass concentrations for EC-containing particles detected by the ATOFMS were found to agree reasonably well with semi-continuous quantitative thermal/optical EC and optical BC measurements (r2 = 0.61 and 0.65–0.68 respectively, n = 552). The EC particle mass assigned to fossil fuel and biomass burning sources also agreed reasonably well with BC mass fractions assigned to the same sources using seven-wavelength aethalometer data (r2 = 0.60 and 0.48, respectively, n = 568). Agreement between the ATOFMS and other instrumentation improved noticeably when a period influenced by significantly aged, internally mixed EC particles was removed from the intercomparison. 88% and 12% of EC particle mass was apportioned to fossil fuel and biomass burning respectively using the ATOFMS data compared with 85% and 15% respectively for BC estimated from the aethalometer model. On average, the mass size distribution for EC particles is bimodal; the smaller mode is attributed to locally emitted, mostly externally mixed EC particles, while the larger mode is dominated by aged, internally mixed ECOCNOx particles associated with continental transport events. Periods of continental influence were identified using the Lagrangian Particle Dispersion Model (LPDM) "FLEXPART". A consistent minimum between the two EC mass size modes was observed at approximately 400 nm for the measurement period. EC particles below this size are attributed to local emissions using chemical mixing state information and contribute 79% of the scaled ATOFMS EC particle mass, while particles above this size are attributed to continental transport events and contribute 21% of the EC particle mass. These results clearly demonstrate the potential benefit of monitoring size-resolved mass concentrations for the separation of local and continental EC emissions. Knowledge of the relative input of these emissions is essential for assessing the effectiveness of local abatement strategies.

scholarly journals Sources and mixing state of size-resolved elemental carbon particles in a European megacity: Paris

2011 ◽  
Vol 11 (11) ◽  
pp. 30333-30380
Author(s):  
R. M. Healy ◽  
J. Sciare ◽  
L. Poulain ◽  
K. Kamili ◽  
M. Merkel ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Biomass Burning ◽  
Single Particle ◽  
Mass Concentration ◽  
Elemental Carbon ◽  
Fossil Fuel ◽  
Time Of Flight ◽  
Particle Mass ◽  
Mass Size ◽  
Mass Concentrations

Abstract. An Aerosol Time-Of-Flight Mass Spectrometer (ATOFMS) was deployed to investigate the size-resolved chemical composition of single particles at an urban background site in Paris, France, as part of the MEGAPOLI winter campaign in January/February 2010. ATOFMS particle counts were scaled to match coincident Twin Differential Mobility Particle Sizer (TDMPS) data in order to generate hourly size-resolved mass concentrations for the single particle classes observed. The total scaled ATOFMS particle mass concentration in the size range 150–1067 nm was found to agree very well with the sum of concurrent High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and Multi-Angle Absorption Photometer (MAAP) mass concentration measurements of organic carbon (OC), inorganic ions and black carbon (BC) (R2 = 0.91). Clustering analysis of the ATOFMS single particle mass spectra allowed the separation of elemental carbon (EC) particles into four classes: (i) EC attributed to biomass burning (ECbiomass), (ii) EC attributed to traffic (ECtraffic), (iii) EC internally mixed with OC and ammonium sulfate (ECOCSOx), and (iv) EC internally mixed with OC and ammonium nitrate (ECOCNOx). Average hourly mass concentrations for EC-containing particles detected by the ATOFMS were found to agree reasonably well with semi-continuous quantitative thermal/optical EC and optical BC measurements (r2 = 0.61 and 0.65–0.68, respectively, n = 552). The EC particle mass assigned to fossil fuel and biomass burning sources also agreed reasonably well with BC mass fractions assigned to the same sources using seven-wavelength aethalometer data (r2 = 0.60 and 0.48, respectively, n = 568). Agreement between the ATOFMS and other instrumentation improved noticeably when a period influenced by significantly aged, internally mixed EC particles was removed from the intercomparison. 88 % and 12 % of EC particle mass was apportioned to fossil fuel and biomass burning respectively using the ATOFMS data compared with 85 % and 15 % respectively for BC estimated from the aethalometer model. On average, the mass size distribution for EC particles is bimodal; the smaller mode is attributed to locally emitted, mostly externally mixed EC particles, while the larger mode is dominated by aged, internally mixed ECOCNOx particles associated with continental transport events. Periods of continental influence were identified using the Lagrangian Particle Dispersion Model (LPDM) "FLEXPART". A consistent minimum between the two EC mass size modes was observed at approximately 400 nm for the measurement period. EC particles below this size are attributed to local emissions using chemical mixing state information and contribute 79 % of the scaled ATOFMS EC particle mass, while particles above this size are attributed to continental transport events and contribute 21 % of the EC particle mass. These results clearly demonstrate the potential benefit of monitoring size-resolved mass concentrations for the separation of local and continental EC emissions. Knowledge of the relative input of these emissions is essential for assessing the effectiveness of local abatement strategies.

scholarly journals Quantification of aerosol chemical composition using continuous single particle measurements

2011 ◽  
Vol 11 (1) ◽  
pp. 1219-1264 ◽  
Author(s):  
C.-H. Jeong ◽  
M. L. McGuire ◽  
K. J. Godri ◽  
J. G. Slowik ◽  
P. J. G. Rehbein ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Organic Carbon ◽  
Mass Spectrometer ◽  
Single Particle ◽  
Elemental Carbon ◽  
Rural Site ◽  
Mass Composition ◽  
Chemical Components ◽  
Particle Measurements ◽  
Mass Concentrations

Abstract. Mass concentrations of particulate matter (PM) chemical components were determined from data for 0.3 to 3.0 μm particles measured by an Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) data at an urban and rural site. Hourly-averaged concentrations of nitrate, sulphate, ammonium, organic carbon, and elemental carbon, estimated based on scaled ATOFMS peak intensities of corresponding ion marker species, were compared with collocated chemical composition measurements by an Aerosol Mass Spectrometer (AMS), a Gas-Particle Ion Chromatograph (GPIC), and a Sunset Lab field OCEC analyzer. The highest correlation was found for nitrate, with correlation coefficients (Pearson r) of 0.89 and 0.85 at the urban and rural sites, respectively. ATOFMS mass calibration factors, determined for the urban site, were used to calculate mass concentrations of the major PM chemical components at the rural site. Mass reconstruction using this ATOFMS based composition data agreed very well with the total PM mass measured at the rural site. Size distributions of the ten main types of particles were resolved for the rural site and the mass composition of each particle type was determined in terms of sulphate, nitrate, ammonium, organic carbon and elemental carbon. This is the first study to estimate hourly mass concentrations of individual aerosol components and the mass composition of individual particle-types based on ATOFMS single particle measurements.

scholarly journals A new method to quantify mineral dust and other aerosol species from aircraft platforms using single-particle mass spectrometry

2019 ◽  
Vol 12 (11) ◽  
pp. 6209-6239 ◽  
Author(s):  
Karl D. Froyd ◽  
Daniel M. Murphy ◽  
Charles A. Brock ◽  
Pedro Campuzano-Jost ◽  
Jack E. Dibb ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Biomass Burning ◽  
Single Particle ◽  
Atmospheric Aerosol ◽  
Mineral Dust ◽  
Sea Salt ◽  
Particle Mass ◽  
Mode Analysis ◽  
Single Particle Mass Spectrometry ◽  
Mass Concentrations

Abstract. Single-particle mass spectrometry (SPMS) instruments characterize the composition of individual aerosol particles in real time. Their fundamental ability to differentiate the externally mixed particle types that constitute the atmospheric aerosol population enables a unique perspective into sources and transformation. However, quantitative measurements by SPMS systems are inherently problematic. We introduce a new technique that combines collocated measurements of aerosol composition by SPMS and size-resolved absolute particle concentrations on aircraft platforms. Quantitative number, surface area, volume, and mass concentrations are derived for climate-relevant particle types such as mineral dust, sea salt, and biomass burning smoke. Additionally, relative ion signals are calibrated to derive mass concentrations of internally mixed sulfate and organic material that are distributed across multiple particle types. The NOAA Particle Analysis by Laser Mass Spectrometry (PALMS) instrument measures size-resolved aerosol chemical composition from aircraft. We describe the identification and quantification of nine major atmospheric particle classes, including sulfate–organic–nitrate mixtures, biomass burning, elemental carbon, sea salt, mineral dust, meteoric material, alkali salts, heavy fuel oil combustion, and a remainder class. Classes can be sub-divided as necessary based on chemical heterogeneity, accumulated secondary material during aging, or other atmospheric processing. Concentrations are derived for sizes that encompass the accumulation and coarse size modes. A statistical error analysis indicates that particle class concentrations can be determined within a few minutes for abundances above ∼10 ng m−3. Rare particle types require longer sampling times. We explore the instrumentation requirements and the limitations of the method for airborne measurements. Reducing the size resolution of the particle data increases time resolution with only a modest increase in uncertainty. The principal limiting factor to fast time response concentration measurements is statistically relevant sampling across the size range of interest, in particular, sizes D < 0.2 µm for accumulation-mode studies and D > 2 µm for coarse-mode analysis. Performance is compared to other airborne and ground-based composition measurements, and examples of atmospheric mineral dust concentrations are given. The wealth of information afforded by composition-resolved size distributions for all major aerosol types represents a new and powerful tool to characterize atmospheric aerosol properties in a quantitative fashion.

scholarly journals Chemical composition of ambient aerosol, ice residues and cloud droplet residues in mixed-phase clouds: single particle analysis during the Cloud and Aerosol Characterization Experiment (CLACE 6)

2009 ◽  
Vol 9 (4) ◽  
pp. 15375-15421 ◽  
Author(s):  
M. Kamphus ◽  
M. Ettner-Mahl ◽  
F. Drewnick ◽  
L. Keller ◽  
D. J. Cziczo ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Single Particle ◽  
Mineral Dust ◽  
Time Of Flight ◽  
Cloud Droplet ◽  
Mixed Phase ◽  
Particle Mass ◽  
Mass Spectrometers ◽  
Flight Mass Spectrometer ◽  
Aerosol Characterization

Abstract. Two different single particle mass spectrometers were operated in parallel at the Swiss High Alpine Research Station Jungfraujoch (JFJ, 3580 m a.s.l.) during the Cloud and Aerosol Characterization Experiment (CLACE 6) in February and March 2007. During mixed phase cloud events ice crystals from 5 μm up to 20 μm were separated from large ice aggregates, non-activated, interstitial aerosol particles and supercooled droplets using an Ice-Counterflow Virtual Impactor (Ice-CVI). During one cloud period supercooled droplets were additionally sampled and analyzed by changing the Ice-CVI setup. The small ice particles and droplets were evaporated by injection into dry air inside the Ice-CVI. The resulting ice and droplet residues (IR and DR) were analyzed for size and composition by two single particle mass spectrometers: a custom-built Single Particle Laser-Ablation Time-of-Flight Mass Spectrometer (SPLAT) and a commercial Aerosol Time of Flight Mass Spectrometer (ATOFMS, TSI Model 3800). During CLACE 6 the SPLAT instrument characterized 355 individual ice residues that produced a mass spectrum for at least one polarity and the ATOFMS measured 152 particles. The mass spectra were binned in classes, based on the combination of dominating substances, such as mineral dust, sulfate, potassium and elemental carbon or organic material. The derived chemical information from the ice residues is compared to the JFJ ambient aerosol that was sampled while the measurement station was out of clouds (several thousand particles analyzed by SPLAT and ATOFMS) and to the composition of the residues of supercooled cloud droplets (SPLAT: 162 cloud droplet residues analyzed, ATOFMS: 1094). The measurements showed that mineral dust particles were strongly enhanced in the ice particle residues. 57% of the SPLAT spectra from ice residues were dominated by signatures from mineral compounds, and 78% of the ATOFMS spectra. Sulfate and nitrate containing particles were strongly depleted in the ice residues. Sulfate was found to dominate the droplet residues (~90% of the particles). The results from the two different single particle mass spectrometers were generally in agreement. Differences in the results originate from several causes, such as the different wavelength of the desorption and ionisation lasers and different size-dependent particle detection efficiencies.

scholarly journals Chemical composition of ambient aerosol, ice residues and cloud droplet residues in mixed-phase clouds: single particle analysis during the Cloud and Aerosol Characterization Experiment (CLACE 6)

2010 ◽  
Vol 10 (16) ◽  
pp. 8077-8095 ◽  
Author(s):  
M. Kamphus ◽  
M. Ettner-Mahl ◽  
T. Klimach ◽  
F. Drewnick ◽  
L. Keller ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Single Particle ◽  
Mineral Dust ◽  
Time Of Flight ◽  
Cloud Droplet ◽  
Mixed Phase ◽  
Particle Mass ◽  
Mass Spectrometers ◽  
Flight Mass Spectrometer ◽  
Aerosol Characterization

Abstract. Two different single particle mass spectrometers were operated in parallel at the Swiss High Alpine Research Station Jungfraujoch (JFJ, 3580 m a.s.l.) during the Cloud and Aerosol Characterization Experiment (CLACE 6) in February and March 2007. During mixed phase cloud events ice crystals from 5–20 μm were separated from larger ice aggregates, non-activated, interstitial aerosol particles and supercooled droplets using an Ice-Counterflow Virtual Impactor (Ice-CVI). During one cloud period supercooled droplets were additionally sampled and analyzed by changing the Ice-CVI setup. The small ice particles and droplets were evaporated by injection into dry air inside the Ice-CVI. The resulting ice and droplet residues (IR and DR) were analyzed for size and composition by the two single particle mass spectrometers: a custom-built Single Particle Laser-Ablation Time-of-Flight Mass Spectrometer (SPLAT) and a commercial Aerosol Time-of-Flight Mass Spectrometer (ATOFMS, TSI Model 3800). During CLACE 6 the SPLAT instrument characterized 355 individual IR that produced a mass spectrum for at least one polarity and the ATOFMS measured 152 IR. The mass spectra were binned in classes, based on the combination of dominating substances, such as mineral dust, sulfate, potassium and elemental carbon or organic material. The derived chemical information from the ice residues is compared to the JFJ ambient aerosol that was sampled while the measurement station was out of clouds (several thousand particles analyzed by SPLAT and ATOFMS) and to the composition of the residues of supercooled cloud droplets (SPLAT: 162 cloud droplet residues analyzed, ATOFMS: 1094). The measurements showed that mineral dust was strongly enhanced in the ice particle residues. Close to all of the SPLAT spectra from ice residues did contain signatures from mineral compounds, albeit connected with varying amounts of soluble compounds. Similarly, close to all of the ATOFMS IR spectra show a mineral or metallic component. Pure sulfate and nitrate containing particles were depleted in the ice residues. Sulfate and nitrate was found to dominate the droplet residues (~90% of the particles). The results from the two different single particle mass spectrometers were generally in agreement. Differences in the results originate from several causes, such as the different wavelength of the desorption and ionisation lasers and different size-dependent particle detection efficiencies.

scholarly journals Organic particle types by single-particle measurements using a time-of-flight aerosol mass spectrometer coupled with a light scattering module

2012 ◽  
Vol 5 (2) ◽  
pp. 3047-3077 ◽  
Author(s):  
S. Liu ◽  
L. M. Russell ◽  
D. T. Sueper ◽  
T. B. Onasch
Keyword(s):  
Light Scattering ◽  
Mass Spectrometer ◽  
Single Particle ◽  
Mass Spectra ◽  
Time Of Flight ◽  
Particle Mass ◽  
Aerosol Mass Spectrometer ◽  
Particle Measurements ◽  
Aerosol Mass ◽  
Organic Particle

Abstract. Chemical and physical properties of individual ambient aerosol particles can vary greatly, so measuring the chemical composition at the single-particle level is essential for understanding atmospheric sources and transformations. Here we describe 46 days of single-particle measurements of atmospheric particles using a time-of-flight aerosol mass spectrometer coupled with a light scattering module (LS-ToF-AMS). The light scattering module optically detects particles larger than 180 nm vacuum aerodynamic diameter (130 nm geometric diameter) (with size resolution of 5–10 defined as dΔd at full width at half maximum) before they arrive at the chemical mass detector and then triggers the saving of single-particle mass spectra. 271 641 particles were detected and sampled during 237 h of sampling in single particle mode. By comparing the timing of light scattering and chemical ion signals for each particle, particle types were classified and their number fractions determined as follows: prompt vaporization (49%), delayed vaporization (7%), and null (44%). LS-ToF-AMS provided the first direct measurement of the size-resolved collection efficiency (CE) of ambient particles, with an approximate 50% number-based CE for particles above detection limit. Prompt and delayed vaporization particles (147 357 particles) were clustered based on similar organic mass spectra (using K-means algorithm) to result in three major clusters: highly oxidized particles (dominated by m/z 44), relatively less oxidized particles (dominated by m/z 43), and particles associated with fresh urban emissions. Each of the three organic clusters had limited chemical properties of other clusters, suggesting that all of the sampled organic particle types were internally mixed to some degree; however, the internal mixing was never uniform and distinct particle types existed throughout the study. Furthermore, the single particle mass spectra and diurnal variations of these clusters agreed well with mass-based components identified (using factor analysis) from simultaneous ensemble-averaged measurements, supporting the connection between ensemble-based factors and atmospheric particle sources and processes. Measurements in this study illustrate that LS-ToF-AMS provides unique information about organic particle types by number as well as mass.

scholarly journals Organic particle types by single-particle measurements using a time-of-flight aerosol mass spectrometer coupled with a light scattering module

2013 ◽  
Vol 6 (2) ◽  
pp. 187-197 ◽  
Author(s):  
S. Liu ◽  
L. M. Russell ◽  
D. T. Sueper ◽  
T. B. Onasch
Keyword(s):  
Light Scattering ◽  
Mass Spectrometer ◽  
Single Particle ◽  
Mass Spectra ◽  
Time Of Flight ◽  
Particle Mass ◽  
Aerosol Mass Spectrometer ◽  
Particle Measurements ◽  
Aerosol Mass ◽  
Organic Particle

Abstract. Chemical and physical properties of individual ambient aerosol particles can vary greatly, so measuring the chemical composition at the single-particle level is essential for understanding atmospheric sources and transformations. Here we describe 46 days of single-particle measurements of atmospheric particles using a time-of-flight aerosol mass spectrometer coupled with a light scattering module (LS-ToF-AMS). The light scattering module optically detects particles larger than 180 nm vacuum aerodynamic diameter (130 nm geometric diameter) before they arrive at the chemical mass spectrometer and then triggers the saving of single-particle mass spectra. 271 641 particles were detected and sampled during 237 h of sampling in single-particle mode. By comparing timing of the predicted chemical ion signals from the light scattering measurement with the measured chemical ion signals by the mass spectrometer for each particle, particle types were classified and their number fractions determined as follows: prompt vaporization (46%), delayed vaporization (6%), and null (48%), where null was operationally defined as less than 6 ions per particle. Prompt and delayed vaporization particles with sufficient chemical information (i.e., more than 40 ions per particle) were clustered based on similarity of organic mass spectra (using k-means algorithm) to result in three major clusters: highly oxidized particles (dominated by m/z 44), relatively less oxidized particles (dominated by m/z 43), and particles associated with fresh urban emissions. Each of the three organic clusters had limited chemical properties of other clusters, suggesting that all of the sampled organic particle types were internally mixed to some degree; however, the internal mixing was never uniform and distinct particle types existed throughout the study. Furthermore, the single-particle mass spectra and time series of these clusters agreed well with mass-based components identified (using factor analysis) from simultaneous ensemble-averaged measurements, supporting the connection between ensemble-based factors and atmospheric particle sources and processes. Measurements in this study illustrate that LS-ToF-AMS provides unique information about organic particle types by number as well as mass.

scholarly journals A new method to quantify mineral dust and other aerosol species from aircraft platforms using single particle mass spectrometry

2019 ◽  
Author(s):  
Karl D. Froyd ◽  
Daniel M. Murphy ◽  
Charles A. Brock ◽  
Pedro Campuzano-Jost ◽  
Jack E. Dibb ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Biomass Burning ◽  
Single Particle ◽  
Atmospheric Aerosol ◽  
Mineral Dust ◽  
Sea Salt ◽  
Particle Mass ◽  
Coarse Mode ◽  
Sampling Statistics ◽  
Mass Concentrations

Abstract. Single-particle mass spectrometer (SPMS) instruments characterize the composition of individual aerosol particles in real time. Their fundamental ability to differentiate the externally mixed particle types that constitute the atmospheric aerosol population enables a unique perspective into sources and transformation. However, quantitative measurements by SPMS systems are inherently problematic. We introduce a new technique that combines collocated measurements of aerosol composition by SPMS and size-resolved absolute particle concentrations on aircraft platforms. Quantitative number, surface area, volume, and mass concentrations are derived for climate-relevant particle types such as mineral dust, sea salt, and biomass burning smoke. Additionally, relative ion signals are calibrated to derive mass concentrations of internally mixed sulfate and organic material that are distributed across multiple particle types. The NOAA Particle Analysis by Laser Mass Spectrometry (PALMS) instrument measures size-resolved aerosol chemical composition from aircraft. We describe the identification and quantification of nine major atmospheric particle classes, including sulfate/organic/nitrate mixtures, biomass burning, elemental carbon, sea salt, mineral dust, meteoric material, alkali salts, heavy fuel oil combustion, and a remainder class. Classes can be sub-divided as necessary based on chemical heterogeneity, accumulated secondary material during aging, or other atmospheric processing. Concentrations are derived for sizes that encompass the accumulation and coarse size modes. A statistical error analysis indicates that particle class concentrations can be determined within a few minutes for abundances above ~ 10 ng m−3. Rare particle types require longer sampling times. We explore the instrumentation requirements and the limitations of the method for airborne measurements. Reducing the size resolution of the particle data increases time resolution with only a modest increase in uncertainty. The principal limiting factor to fast time response concentration measurements is statistically relevant sampling across the size range of interest, in particular, sizes D  2 μm for coarse mode analysis. We demonstrate the use of a virtual impactor to enhance sampling statistics for the inherently sparse coarse mode. Performance is compared to other airborne and ground-based composition measurements, and examples of atmospheric mineral dust concentrations are given. The wealth of information afforded by composition-resolved size distributions for all major aerosol types represents a new and powerful tool to characterize atmospheric aerosol properties in a quantitative fashion.

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