scholarly journals Characterization of submicron organic particles in Beijing during summertime: comparison between SP-AMS and HR-AMS

2020 ◽  
Vol 20 (22) ◽  
pp. 14091-14102
Author(s):  
Junfeng Wang ◽  
Jianhuai Ye ◽  
Dantong Liu ◽  
Yangzhou Wu ◽  
Jian Zhao ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Mass Spectrometer ◽  
Biomass Burning ◽  
Collection Efficiency ◽  
Radiation Balance ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Unique Factor ◽  
Organic Particles ◽  
Beijing China

Abstract. Black carbon (BC) particles in Beijing summer haze play an important role in the regional radiation balance and related environmental processes. Understanding the factors that lead to variability of the impacts of BC remains limited. Here, we present observations by a soot-particle aerosol mass spectrometer (SP-AMS) of BC-containing submicron particulate matter (BC−PM1) in Beijing, China, during summer 2017. These observations were compared to concurrently measured total non-refractory submicron particulate matter (NR−PM1) by a high-resolution aerosol mass spectrometer (HR-AMS). Distinct properties were observed between NR−PM1 and BC−PM1 relevant to organic aerosol (OA) composition. Hydrocarbon-like OA (HOA) in BC−PM1 was found to be up to 2-fold higher than that in NR−PM1 in fresh vehicle emissions, suggesting that a part of HOA in BC−PM1 may be overestimated, likely due to the change of collection efficiency of SP-AMS. Cooking-related OA was only identified in NR−PM1, whereas aged biomass burning OA (A-BBOA) was a unique factor only identified in BC−PM1. The A-BBOA was linked to heavily coated BC, which may lead to enhancement of the light absorption ability of BC by a factor of 2 via the “lensing effect”. More-oxidized oxygenated OA identified in BC-containing particles was found to be slightly different from that observed by HR-AMS, mainly due to the influence of A-BBOA. Overall, these findings highlight that BC in urban Beijing is partially of agricultural fire origin and that a unique biomass-burning-related OA associated with BC may be ubiquitous in aged BC−PM1, and this OA may play a role in affecting air quality and climate that has not previously been fully considered.

scholarly journals Characterization of Submicron Organic Particles in Beijing During Summertime: Comparison Between SP-AMS and HR-AMS

2020 ◽  
Author(s):  
Junfeng Wang ◽  
Jianhuai Ye ◽  
Dantong Liu ◽  
Yangzhou Wu ◽  
Jian Zhao ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Mass Spectrometer ◽  
Biomass Burning ◽  
Collection Efficiency ◽  
Radiation Balance ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Unique Factor ◽  
Organic Particles ◽  
Beijing China

Abstract. Black carbon (BC) particles in Beijing summer haze play an important role in regional radiation balance and related environmental processes. Understanding the factors that lead to variability in the impacts of BC remains limited. Here, we present observations by a soot-particle aerosol mass spectrometer of BC-containing submicron particulate matter (BC-PM1) in the summer of 2017 in Beijing, China. These observations were compared to concurrently measured total non-refractory submicron particulate matter (NR-PM1) by a high-resolution aerosol mass spectrometer (HR-AMS). Distinct properties were observed between NR-PM1 and BC-PM1 related to organic aerosol (OA) composition with hydrocarbon-like OA in BC-PM1 up to two-fold higher than that in NR-PM1 in fresh vehicle emissions, suggesting that a part of HOA in BC-PM1 may be overestimated due to the change of the collection efficiency of SP-AMS. Cooking-related OA was only identified in NR-PM1, whereas aged biomass burning OA (A-BBOA) was a unique factor only identified in BC-PM1. The A-BBOA was linked to those heavily coated BC, which may lead to enhancement of light absorption ability of BC by a factor of two via the “lensing effect”. More-oxidized oxygenated OA identified in BC-containing particles was found to be slightly different from that observed by HR-AMS, mainly due to the influence of A-BBOA. Overall, these findings highlight that BC in urban Beijing is partly of agricultural fire origin and, a unique biomass burning-related OA associated with BC may be ubiquitous in aged BC-PM1, and this OA may play a role in affecting air quality and climate that has not previously been fully considered.

scholarly journals Single-particle measurements of bouncing particles and in situ collection efficiency from an airborne aerosol mass spectrometer (AMS) with light-scattering detection

2017 ◽  
Vol 10 (10) ◽  
pp. 3801-3820 ◽  
Author(s):  
Jin Liao ◽  
Charles A. Brock ◽  
Daniel M. Murphy ◽  
Donna T. Sueper ◽  
André Welti ◽  
...  
Keyword(s):  
Light Scattering ◽  
Mass Spectrometer ◽  
Single Particle ◽  
Total Mass ◽  
Mass Spectra ◽  
Collection Efficiency ◽  
Aerosol Mass Spectrometer ◽  
Mass Spectral ◽  
Aerosol Mass ◽  
Spectral Signal

Abstract. A light-scattering module was coupled to an airborne, compact time-of-flight aerosol mass spectrometer (LS-AMS) to investigate collection efficiency (CE) while obtaining nonrefractory aerosol chemical composition measurements during the Southeast Nexus (SENEX) campaign. In this instrument, particles scatter light from an internal laser beam and trigger saving individual particle mass spectra. Nearly all of the single-particle data with mass spectra that were triggered by scattered light signals were from particles larger than ∼ 280 nm in vacuum aerodynamic diameter. Over 33 000 particles are characterized as either prompt (27 %), delayed (15 %), or null (58 %), according to the time and intensity of their total mass spectral signals. The particle mass from single-particle spectra is proportional to that derived from the light-scattering diameter (dva-LS) but not to that from the particle time-of-flight (PToF) diameter (dva-MS) from the time of the maximum mass spectral signal. The total mass spectral signal from delayed particles was about 80 % of that from prompt ones for the same dva-LS. Both field and laboratory data indicate that the relative intensities of various ions in the prompt spectra show more fragmentation compared to the delayed spectra. The particles with a delayed mass spectral signal likely bounced off the vaporizer and vaporized later on another surface within the confines of the ionization source. Because delayed particles are detected by the mass spectrometer later than expected from their dva-LS size, they can affect the interpretation of particle size (PToF) mass distributions, especially at larger sizes. The CE, measured by the average number or mass fractions of particles optically detected that had measurable mass spectra, varied significantly (0.2–0.9) in different air masses. The measured CE agreed well with a previous parameterization when CE > 0.5 for acidic particles but was sometimes lower than the minimum parameterized CE of 0.5.

scholarly journals Collection efficiency of the soot-particle aerosol mass spectrometer (SP-AMS) for internally mixed particulate black carbon

2014 ◽  
Vol 7 (12) ◽  
pp. 4507-4516 ◽  
Author(s):  
M. D. Willis ◽  
A. K. Y. Lee ◽  
T. B. Onasch ◽  
E. C. Fortner ◽  
L. R. Williams ◽  
...  
Keyword(s):  
Laser Beam ◽  
Black Carbon ◽  
Mass Spectrometer ◽  
Soot Particle ◽  
Collection Efficiency ◽  
Particle Beam ◽  
Aerosol Mass Spectrometer ◽  
Coated Particles ◽  
Aerosol Mass ◽  
Wide Range

Abstract. The soot-particle aerosol mass spectrometer (SP-AMS) uses an intra-cavity infrared laser to vaporize refractory black carbon (rBC) containing particles, making the particle beam–laser beam overlap critical in determining the collection efficiency (CE) for rBC and associated non-refractory particulate matter (NR-PM). This work evaluates the ability of the SP-AMS to quantify rBC and NR-PM mass in internally mixed particles with different thicknesses of organic coating. Using apparent relative ionization efficiencies for uncoated and thickly coated rBC particles, we report measurements of SP-AMS sensitivity to NR-PM and rBC, for Regal Black, the recommended particulate calibration material. Beam width probe (BWP) measurements are used to illustrate an increase in sensitivity for highly coated particles due to narrowing of the particle beam, which enhances the CE of the SP-AMS by increasing the laser beam–particle beam overlap. Assuming complete overlap for thick coatings, we estimate CE for bare Regal Black particles of 0.6 ± 0.1, which suggests that previously measured SP-AMS sensitivities to Regal Black were underestimated by up to a factor of 2. The efficacy of the BWP measurements is highlighted by studies at a busy road in downtown Toronto and at a non-roadside location, which show particle beam widths similar to, but greater than that of bare Regal Black and coated Regal Black, respectively. Further BWP measurements at field locations will help to constrain the range of CE for fresh and aged rBC-containing particles. The ability of the SP-AMS to quantitatively assess the composition of internally mixed particles is validated through measurements of laboratory-generated organic coated particles, which demonstrate that the SP-AMS can quantify rBC and NR-PM over a wide range of particle compositions and rBC core sizes.

scholarly journals Online mass spectrometric aerosol measurements during the MINOS campaign (Crete, August 2001)

2004 ◽  
Vol 4 (1) ◽  
pp. 65-80 ◽  
Author(s):  
J. Schneider ◽  
S. Borrmann ◽  
A. G. Wollny ◽  
M. Bläsner ◽  
N. Mihalopoulos ◽  
...  
Keyword(s):  
Ammonium Sulfate ◽  
Mass Spectrometer ◽  
Biomass Burning ◽  
Eastern Mediterranean ◽  
Mass Spectrometric ◽  
Particle Analysis ◽  
Spectrometric Analysis ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Fine Mode

Abstract. Mass spectrometric analysis of volatile and semi-volatile (=non-refractory) aerosol particles have been performed during a field study in the summer Eastern Mediterranean. A size-resolved, quantitative mass spectrometric technique (the Aerodyne Aerosol Mass Spectrometer, AMS) has been used, and the results are compared to filter sampling methods and particle sizing techniques. The different techniques agree with the finding that the fine particle mode (D<1.2 mm) consisted mostly of ammonium sulfate and of organic material. The aerosol sulfate ranged between 2 and 12 mg/m3. On most days, ammonium was closely correlated with sulfate, suggesting ammonium sulfate as the major aerosol component, but on days with high sulfate mass concentrations, the sulfate was not fully neutralized by ammonium. Trajectories indicate that the aerosol and/or its precursors originate from South-Eastern Europe. The source of the ammonium sulfate aerosol is most likely fossil fuel burning, whereas the organic aerosol may also originate from biomass burning. Ion series analysis of the organics fraction in the mass spectrometer indicated that the major component of the organics were oxygenated organics which are a marker for aged, photochemically processed aerosol or biomass burning aerosol. The non-refractory aerosol compounds, measured with the Aerosol Mass Spectrometer, contributed between 37 and 50% to the total aerosol mass in the fine mode. A second mass spectrometer for single particle analysis by laser ablation has been used for the first time in the field during this study and yielded results, which agree with filter samples of the coarse particle mode. This mode consisted of sea salt particles and dust aerosol.

Using Raman-lidar-based regularized microphysical retrievals and Aerosol Mass Spectrometer measurements for the characterization of biomass burning aerosols

2015 ◽  
Vol 299 ◽  
pp. 156-174 ◽  
Author(s):  
Stefanos Samaras ◽  
Doina Nicolae ◽  
Christine Böckmann ◽  
Jeni Vasilescu ◽  
Ioannis Binietoglou ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Biomass Burning ◽  
Raman Lidar ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass

Source apportionment of time- and size-resolved particulate matter over two sites in New Delhi & NCR

2020 ◽  
Author(s):  
Suneeti Mishra ◽  
Sachchida Tripathi ◽  
Navaneeth Thamban ◽  
Vipul Lalchandani ◽  
Varun Kumar ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Source Apportionment ◽  
Mass Spectrometer ◽  
Time Of Flight ◽  
Aerosol Mass Spectrometer ◽  
Ambient Aerosol ◽  
Atmospheric Processes ◽  
Aerosol Mass ◽  
Individual Site ◽  
Institute Of Technology

&lt;p&gt;Size resolved data of chemical species carries a lot of latent information about the sources and atmospheric processes which lead to their formation and growth. Source apportionment techniques on organic or inorganic aerosols provide a fair amount of information about the sources but this analysis only provides a partial picture owing to the complicated nature of the ambient aerosols which may contain both, organic as well as inorganic particulate matter. Traditionally, potential emission sources are distinguished by either the organic or inorganic tracers present in ambient aerosol, but recently several studies have performed PMF on both the species (Sun et al, 2012). However, it tells more about the final transformed products which could be formed from different pathways but not much about the transformation pathways. Insights about the source and the atmospheric processes involved can be derived from the analysis of size-resolved data of the ambient aerosol. PMF on Size-resolved information helps us to narrow down the possible pathways of the transformed products.&lt;/p&gt;&lt;p&gt;However, there is very limited literature available to help us understand more about size-resolved bulk particulate matter. In this manuscript, a novel approach to perform Positive Matrix Factorization (PMF) on real-time size-resolved Unit Mass Resolution (UMR) data from Aerosol Mass Spectrometer (AMS) is presented. Both size- and time-resolved PMF is performed on non-refractory particle composition (organic &amp; inorganic) on the UMR PTOF data of two sites in one of the most polluted cities in the world. The sampling through Long Time of flight mass spectrometer (LToF-AMS) was carried out at Indian Institute of Technology, Delhi which is located in Hauz Khaz area, at the heart of Delhi NCR, whereas parallel sampling through High-resolution Time of flight aerosol mass spectrometer (HR-ToF-AMS) was carried out at Manav Rachna University which is located in Faridabad within Delhi NCR at a downwind location. PMF was performed on the data by using Multi-linear Engine (ME-2) on PMF model by SoFi (Source Finder) tool. A seven-factor solution was chosen based on the factor profiles, time series, diurnals and correlation with the external factors obtained by supplementary instruments. The size-resolved spectra of the species at an individual site was studied and the difference between the sites was compared.&lt;/p&gt;

scholarly journals Single particle characterization using a light scattering module coupled to a time-of-flight aerosol mass spectrometer

2009 ◽  
Vol 9 (20) ◽  
pp. 7769-7793 ◽  
Author(s):  
E. S. Cross ◽  
T. B. Onasch ◽  
M. Canagaratna ◽  
J. T. Jayne ◽  
J. Kimmel ◽  
...  
Keyword(s):  
Light Scattering ◽  
Mass Spectrometer ◽  
Single Particle ◽  
Collection Efficiency ◽  
Time Of Flight ◽  
Chemical Compositions ◽  
Single Particles ◽  
Mixing State ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass

Abstract. We present the first single particle results obtained with an Aerodyne time-of-flight aerosol mass spectrometer coupled with a light scattering module (LS-ToF-AMS). The instrument was deployed at the T1 ground site approximately 40 km northeast of the Mexico City Metropolitan Area as part of the MILAGRO field study in March of 2006. The LS-ToF-AMS acquires both ensemble average and single particle data. Over a 75-h sampling period from 27–30 March 2006, 12 853 single particle mass spectra were optically-triggered and saved. The single particles were classified based on observed vaporization histories and measured chemical compositions. The single particle data is shown to provide insights on internal AMS collection efficiencies and ambient mixing state information that augments the ensemble data. Detection of correlated light scattering and chemical ion signals allowed for a detailed examination of the vaporization/ionization process for single particles measured with the AMS instrument. Three particle vaporization event types were identified as a fraction of the total number of particles detected: (1) 23% with prompt vaporization, (2) 26% with delayed vaporization, and (3) 51% characterized as null. Internal consistency checks show that average single particle nonrefractory mass and chemical composition measurements were in reasonable agreement with ensemble measurements and suggest that delayed and null vaporization events are the dominant source of the nonunit collection efficiency of the AMS. Taken together, the simultaneous prompt single particle and aerosol ensemble measurements offer insight into the mixing state and atmospheric transformations of ambient aerosol particles.

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