scholarly journals Determination of PM1 Sources at a Prague Background Site during the 2012–2013 Period Using PMF Analysis of Combined Aerosol Mass Spectra

Atmosphere ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 20
Author(s):  
Otakar Makeš ◽  
Jaroslav Schwarz ◽  
Petr Vodička ◽  
Guenter Engling ◽  
Vladimír Ždímal
Keyword(s):  
Mass Spectra ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Additional Input ◽  
Daily Cycles ◽  
Aerosol Sources ◽  
Mass Profile ◽  
Inorganic Aerosol ◽  
Measurement Campaigns

Two intensive measurement campaigns using a compact time-of-flight aerosol mass spectrometer were carried out at the suburban site in Prague (Czech Republic) in summer (2012) and winter (2013). The aim was to determine the aerosol sources of the NR-PM1 fraction by PMF analysis of organic (OA) and inorganic aerosol mass spectra. Firstly, an analysis of the OA mass spectra was performed. Hydrocarbon-like OA (HOA), biomass burning OA (BBOA), and two types of oxygenated OA (OOA1) and (OOA2) were identified in summer. In winter, HOA, BBOA, long-range oxygenated OA (LROOA), and local oxygenated OA (LOOA) were determined. The identified HOA and BBOA factors were then used as additional input for the subsequent ME-2 analysis of the combined organic and inorganic spectra. This analysis resulted in six factors in both seasons. All of the previously reported organic factors were reidentified and expanded with the inorganic part of the spectra in both seasons. Two predominantly inorganic factors ammonium sulphate (AMOS) and ammonium nitrate (AMON) were newly identified in both seasons. Despite very similar organic parts of the mass profiles, the daily cycles of HOA and LOOA differed significantly in winter. It appears that the addition of the inorganic part of the mass profile, in some cases, reduces the ability of the model to identify physically meaningful factors.

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.

Chemical characterization of fine particulate matter, and source apportionment of organic aerosol at three sites in New Delhi, India

2020 ◽  
Author(s):  
Sachchida Tripathi ◽  
Vipul Lalchandani ◽  
Varun Kumar ◽  
Anna Tobler ◽  
Navaneeth Thamban ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Mass Spectra ◽  
Fine Particulate Matter ◽  
Time Of Flight ◽  
Chemical Characterization ◽  
New Delhi ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Fine Particulate

<p>Atmospheric particulate matter has adverse effects on human health, and causes over 4 million deaths per year globally. New Delhi was ranked as world’s most polluted megacity with annual average PM<sub>2.5</sub> concentration of ~140 ug.m<sup>-3</sup>. Thus, real time chemical characterization of fine particulate matter and identification of its sources is important for developing cost effective mitigation policies.</p><p>Highly time resolved real-time chemical composition of PM<sub>2.5</sub> was measured using Long-Time of Flight-Aerosol Mass Spectrometer (L-ToF-AMS) at Indian Institute of Technology Delhi and Time of Flight-Aerosol Chemical Speciation Monitor (ToF-ACSM) at Indian Institute of Tropical Meteorology, Delhi, and PM<sub>1 </sub>using High Resolution-Time of Flight-Aerosol Mass Spectrometer (HR-ToF-AMS) at Manav Rachna International University, Faridabad, Haryana located ~40 km downwind of Delhi during Jan-March, 2018. Black carbon concentration was measured using Aethalometer at all three sites. Unit mass resolution (UMR) and high resolution (HR) data analysis were performed on AMS and ACSM mass spectra to calculate organics, nitrate, sulfate and chloride concentrations. Positive Matrix Factorization (PMF) (Paatero and Tapper, 1994) of organic mass spectra was performed by applying multilinear engine (ME-2) algorithm using Sofi (Source finder) for identifying sources of OA.</p>

scholarly journals Relating hygroscopicity and composition of organic aerosol particulate matter

2011 ◽  
Vol 11 (3) ◽  
pp. 1155-1165 ◽  
Author(s):  
J. Duplissy ◽  
P. F. DeCarlo ◽  
J. Dommen ◽  
M. R. Alfarra ◽  
A. Metzger ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Field Experiments ◽  
Organic Aerosol ◽  
Photochemical Oxidation ◽  
Ionization Mass ◽  
Hygroscopic Growth ◽  
Atmospheric Models ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Organic Precursors

Abstract. A hygroscopicity tandem differential mobility analyzer (HTDMA) was used to measure the water uptake (hygroscopicity) of secondary organic aerosol (SOA) formed during the chemical and photochemical oxidation of several organic precursors in a smog chamber. Electron ionization mass spectra of the non-refractory submicron aerosol were simultaneously determined with an aerosol mass spectrometer (AMS), and correlations between the two different signals were investigated. SOA hygroscopicity was found to strongly correlate with the relative abundance of the ion signal m/z 44 expressed as a fraction of total organic signal (f44). m/z 44 is due mostly to the ion fragment CO2+ for all types of SOA systems studied, and has been previously shown to strongly correlate with organic O/C for ambient and chamber OA. The analysis was also performed on ambient OA from two field experiments at the remote site Jungfraujoch, and the megacity Mexico City, where similar results were found. A simple empirical linear relation between the hygroscopicity of OA at subsaturated RH, as given by the hygroscopic growth factor (GF) or "ϰorg" parameter, and f44 was determined and is given by ϰorg = 2.2 × f44 − 0.13. This approximation can be further verified and refined as the database for AMS and HTDMA measurements is constantly being expanded around the world. The use of this approximation could introduce an important simplification in the parameterization of hygroscopicity of OA in atmospheric models, since f44 is correlated with the photochemical age of an air mass.

scholarly journals SoFi, an Igor based interface for the efficient use of the generalized multilinear engine (ME-2) for source apportionment: application to aerosol mass spectrometer data

2013 ◽  
Vol 6 (4) ◽  
pp. 6409-6443 ◽  
Author(s):  
F. Canonaco ◽  
M. Crippa ◽  
J. G. Slowik ◽  
U. Baltensperger ◽  
A. S. H. Prévôt
Keyword(s):  
Source Apportionment ◽  
Mass Spectra ◽  
A Priori ◽  
Aerosol Mass Spectrometer ◽  
Pmf Model ◽  
Aerosol Mass ◽  
Five Factors ◽  
Multilinear Engine ◽  
Constrained Models ◽  
Spectrometer Data

Abstract. Source apportionment using the bilinear model through the multilinear engine (ME-2) was successfully applied to non-refractory organic aerosol (OA) mass spectra collected during winter 2011 and 2012 in Zurich, Switzerland using the aerosol chemical speciation monitor ACSM. Five factors were identified: low-volatility oxygenated OA (LV-OOA), semivolatile oxygenated OA (SV-OOA), hydrocarbon-like OA (HOA), cooking OA (COA) and biomass burning OA (BBOA). A graphical user interface SoFi (Source Finder) was developed at PSI in order to facilitate the testing of different rotational techniques available within the ME-2 engine by providing a priori factor profiles for some or all of the expected factors. ME-2 was used to test the positive matrix factorization (PMF) model, the fully constrained chemical mass balance (CMB) model, and partially constrained models utilizing a values and pulling equations. Within the set of model solutions determined to be environmentally reasonable, BBOA and SV-OOA factor mass spectra and time series showed the greatest variability. This variability represents uncertainty in the model solution and indicates that analysis of model rotations provides a useful approach for assessing the uncertainty of bilinear source apportionment models.

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

2012 ◽  
Vol 12 (5) ◽  
pp. 13299-13335
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 Nitrates ◽  
Aerosol Mass Spectrometer ◽  
Inorganic Aerosols ◽  
Aerosol Mass ◽  
Inorganic Species ◽  
Mixing Characteristics

Abstract. The high resolution mass spectra of organic and inorganic aerosols from aerosol mass spectrometer (AMS) measurements were first combined into positive matrix factorization (PMF) analysis to investigate the sources and evolution processes of atmospheric aerosols. The new approach is able to study the mixing of organic aerosols (OA) and inorganic species, the acidity of OA factors, and the fragment ion patterns related to photochemical processing. In this study, PMF analysis of the unified AMS spectral matrices resolved 8 factors for the submicron aerosols measured at Queens College in New York City in summer 2009. The hydrocarbon-like OA (HOA) and cooking OA (COA) contain very minor inorganic species, indicating the different sources and mixing characteristics between primary OA and secondary species. The two factors that are primarily ammonium sulfate (SO4-OA) and ammonium nitrate (NO3-OA), respectively, are overall neutralized, of which the OA in SO4-OA shows the highest oxidation state (O/C = 0.69) among OA factors. The semi-volatile oxygenated OA comprises two components, i.e., a less oxidized (LO-OOA) and a more oxidized (MO-OOA). The MO-OOA represents a local photochemical product with the diurnal profile exhibiting a pronounced noon peak, consistent with those of formaldehyde (HCHO) and Ox (= O3+NO2). The much higher NO+/NO2+ fragment ion ratio in MO-OOA than that from ammonium nitrate alone provides evidence for the formation of organic nitrates. The amine-related nitrogen-enriched OA (NOA) contains ~25% of acidic inorganic salts, elucidating the formation of secondary OA from amines in acidic environments. The size distributions derived from 3-dimensional size-resolved mass spectra show distinct diurnal evolving behaviors for different OA factors, but overall a progressing evolution from smaller to larger particle mode as a function of oxidation states. Our results demonstrate that PMF analysis by incorporating inorganic aerosols is of importance for gaining more insights into the sources and processes, mixing characteristics, and acidity of OA.

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 Organic aerosol components derived from 25 AMS data sets across Europe using a consistent ME-2 based source apportionment approach

2014 ◽  
Vol 14 (12) ◽  
pp. 6159-6176 ◽  
Author(s):  
M. Crippa ◽  
F. Canonaco ◽  
V. A. Lanz ◽  
M. Äijälä ◽  
J. D. Allan ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Monitoring And Evaluation ◽  
Organic Aerosol ◽  
Data Sets ◽  
Time Resolved ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Ambient Data ◽  
Aerosol Sources ◽  
Different Sources

Abstract. Organic aerosols (OA) represent one of the major constituents of submicron particulate matter (PM1) and comprise a huge variety of compounds emitted by different sources. Three intensive measurement field campaigns to investigate the aerosol chemical composition all over Europe were carried out within the framework of the European Integrated Project on Aerosol Cloud Climate and Air Quality Interactions (EUCAARI) and the intensive campaigns of European Monitoring and Evaluation Programme (EMEP) during 2008 (May–June and September–October) and 2009 (February–March). In this paper we focus on the identification of the main organic aerosol sources and we define a standardized methodology to perform source apportionment using positive matrix factorization (PMF) with the multilinear engine (ME-2) on Aerodyne aerosol mass spectrometer (AMS) data. Our source apportionment procedure is tested and applied on 25 data sets accounting for two urban, several rural and remote and two high altitude sites; therefore it is likely suitable for the treatment of AMS-related ambient data sets. For most of the sites, four organic components are retrieved, improving significantly previous source apportionment results where only a separation in primary and secondary OA sources was possible. Generally, our solutions include two primary OA sources, i.e. hydrocarbon-like OA (HOA) and biomass burning OA (BBOA) and two secondary OA components, i.e. semi-volatile oxygenated OA (SV-OOA) and low-volatility oxygenated OA (LV-OOA). For specific sites cooking-related (COA) and marine-related sources (MSA) are also separated. Finally, our work provides a large overview of organic aerosol sources in Europe and an interesting set of highly time resolved data for modeling purposes.

scholarly journals The hygroscopicity parameter (κ) of ambient organic aerosol at a field site subject to biogenic and anthropogenic influences: Relationship to degree of aerosol oxidation

2009 ◽  
Vol 9 (6) ◽  
pp. 25323-25360 ◽  
Author(s):  
R. Y.-W. Chang ◽  
J. G. Slowik ◽  
N. C. Shantz ◽  
A. Vlasenko ◽  
J. Liggio ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Cloud Condensation Nuclei ◽  
Statistical Technique ◽  
Organic Component ◽  
Rural Site ◽  
Field Site ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Kohler Theory ◽  
Good Agreement

Abstract. Cloud condensation nuclei (CCN) concentrations were measured at a rural site in Ontario, Canada during the spring of 2007. The CCN concentrations were compared to values predicted from the aerosol chemical composition and size distribution using κ-Köhler theory. The hygroscopicity of the organic component was characterised by two methods, both of which are based on the aerosol's degree of oxygenation as determined by the mass spectra measured with an Aerodyne aerosol mass spectrometer. The first approach uses a statistical technique, positive matrix factorization (PMF), to separate hygroscopic and non-hygroscopic factors while the second uses the O/C, which is an indication of the aerosol's degree of oxygenation. In both cases, the hygroscopicity parameter (κ) of the organic component is varied so that the predicted and measured CCN concentrations are internally consistent and in good agreement. By focussing on a small number of organic components defined by their composition, we can simplify the estimates needed to describe the aerosol's hygroscopicity. We find that κ of the oxygenated organic component from the PMF analysis is 0.20±0.03 while κ of the entire organic component can be parameterized as κorg=(0.30±0.05)×(O/C).

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