scholarly journals Sources and atmospheric processing of wintertime aerosols in Seoul, Korea: Insights from real-time measurements using a high-resolution aerosol mass spectrometer

2016 ◽  
Author(s):  
Hwajin Kim ◽  
Qi Zhang ◽  
Gwi-Nam Bae ◽  
Jin Young Kim ◽  
Seung Bok Lee
Keyword(s):  
Particulate Matter ◽  
High Resolution ◽  
Real Time ◽  
Mass Spectrometer ◽  
Organic Aerosol ◽  
Meteorological Conditions ◽  
Emission Sources ◽  
Aerosol Mass Spectrometer ◽  
Atmospheric Processes ◽  
Aerosol Mass

Abstract. Highly time-resolved chemical characterization of non-refractory submicrometer particulate matter (NR-PM1) was conducted in Seoul, the capital and largest metropolis of Korea, using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). The measurements were performed during winter, when elevated particulate matter (PM) pollution events are often observed. This is the first time that detailed real-time aerosol measurement results are reported from Seoul, Korea, which reveal valuable insights into the sources and atmospheric processes that contribute to PM pollution in this region. The average concentration of submicron aerosol (PM1 = NR - PM1 + black carbon (BC)) was 27.5 µg m−3, and the total mass was dominated by organics (44 %), followed by nitrate (24 %) and sulfate (10 %). The average atomic ratios of oxygen-to-carbon (O / C), hydrogen-to-carbon (H / C), and nitrogen-to-carbon (N / C) of organic aerosol (OA) were 0.37, 1.79, and 0.022, respectively, which gives that average organic mass-to-carbon (OM / OC) ratio of 1.67. The concentrations (2.6–90.7 µg m−3) and composition of PM1 varied dynamically during the measurement period, due to the influences of different meteorological conditions, emission sources, and air mass origins. Five distinct sources of OA were identified via positive matrix factorization (PMF) analysis of the HR-ToF-AMS data: vehicle emissions represented by a hydrocarbon like OA factor (HOA; O / C = 0.06), cooking activities represented by a cooking OA factor (COA; O / C = 0.15), wood combustion represented by a biomass burning OA factor (BBOA; O / C = 0.34), and secondary organic aerosol (SOA) represented by a semi-volatile oxygenated OA factor (SV-OOA; O / C = 0.56) and a low volatility oxygenated OA factor (LV-OOA; O / C = 0.68). On average, primary OA (POA = HOA + COA + BBOA) accounted for 59 % the OA mass whereas SV-OOA and LV-OOA contributed 15 % and 26 %, respectively. Our results indicate that air quality in Seoul during winter is influenced strongly by secondary aerosol formation with sulfate, nitrate, ammonium, SV-OOA, and LV-OOA together accounting for 64 % of the PM1 mass during this study. However, aerosol sources and composition were found to be significantly different between clean and polluted periods. During stagnant periods with low wind speed (WS) and high relative humidity (RH), PM concentration was generally high (average ± 1σ = 43.6 ± 12.4 µg m−3) with enhanced fractions of nitrate (27 %) and SV-OOA (8 %), which suggested a strong influence from local production of secondary aerosol. Low PM loading periods (12.6 ± 7.1 µg m−3) tended to occurred under higher WS and lower RH conditions and appeared to be more strongly influenced by regional air masses, as indicated by higher mass fractions of sulfate (12 %) and LV-OOA (21 %) in PM1. Overall, our results indicate that PM pollutants in urban Korea originate from complex emission sources and atmospheric processes and that their concentrations and composition are controlled by various factors including meteorological conditions, local anthropogenic emissions, and upwind sources.

scholarly journals Sources and atmospheric processing of winter aerosols in Seoul, Korea: insights from real-time measurements using a high-resolution aerosol mass spectrometer

2017 ◽  
Vol 17 (3) ◽  
pp. 2009-2033 ◽  
Author(s):  
Hwajin Kim ◽  
Qi Zhang ◽  
Gwi-Nam Bae ◽  
Jin Young Kim ◽  
Seung Bok Lee
Keyword(s):  
Particulate Matter ◽  
High Resolution ◽  
Real Time ◽  
Mass Spectrometer ◽  
Meteorological Conditions ◽  
Emission Sources ◽  
Aerosol Mass Spectrometer ◽  
Secondary Aerosol ◽  
Atmospheric Processes ◽  
Aerosol Mass

Abstract. Highly time-resolved chemical characterization of nonrefractory submicrometer particulate matter (NR-PM1) was conducted in Seoul, the capital and largest metropolis of Korea, using an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). The measurements were performed during winter, when elevated particulate matter (PM) pollution events are often observed. This is the first time that detailed real-time aerosol measurement results have been reported from Seoul, Korea, and they reveal valuable insights into the sources and atmospheric processes that contribute to PM pollution in this region. The average concentration of submicron aerosol (PM1 =  NR-PM1+ black carbon (BC)) was 27.5 µg m−3, and the total mass was dominated by organics (44 %), followed by nitrate (24 %) and sulfate (10 %). The average atomic ratios of oxygen to carbon (O / C), hydrogen to carbon (H / C), and nitrogen to carbon (N / C) of organic aerosols (OA) were 0.37, 1.79, and 0.018, respectively, which result in an average organic mass-to-carbon (OM / OC) ratio of 1.67. The concentrations (2.6–90.7 µg m−3) and composition of PM1 varied dynamically during the measurement period due to the influences of different meteorological conditions, emission sources, and air mass origins. Five distinct sources of OA were identified via positive matrix factorization (PMF) analysis of the HR-ToF-AMS data: vehicle emissions represented by a hydrocarbon-like OA factor (HOA, O / C  =  0.06), cooking activities represented by a cooking OA factor (COA, O / C  =  0.14), wood combustion represented by a biomass burning OA factor (BBOA, O / C  =  0.34), and secondary organic aerosol (SOA) represented by a semivolatile oxygenated OA factor (SV-OOA, O / C  = 0.56) and a low-volatility oxygenated OA factor (LV-OOA, O / C  =  0.68). On average, primary OA (POA = HOA + COA + BBOA) accounted for 59 % the OA mass, whereas SV-OOA and LV-OOA contributed 15 and 26 %, respectively. Our results indicate that air quality in Seoul during winter is influenced strongly by secondary aerosol formation, with sulfate, nitrate, ammonium, SV-OOA, and LV-OOA together accounting for 64 % of the PM1 mass during this study. However, aerosol sources and composition were found to be significantly different between clean and polluted periods. During stagnant periods with low wind speed (WS) and high relative humidity (RH), PM concentration was generally high (average ±1σ = 43.6 ± 12.4 µg m−3) with enhanced fractions of nitrate (27 %) and SV-OOA (8 %), which suggested a strong influence from local production of secondary aerosol. Low-PM loading periods (12.6 ± 7.1 µg m−3) tended to occur under higher-WS and lower-RH conditions and appeared to be more strongly influenced by regional air masses, as indicated by higher mass fractions of sulfate (12 %) and LV-OOA (20 %) in PM1. Overall, our results indicate that PM pollutants in urban Korea originate from complex emission sources and atmospheric processes and that their concentrations and composition are controlled by various factors, including meteorological conditions, local anthropogenic emissions, and upwind sources.

scholarly journals Highly time-resolved chemical characterization of atmospheric submicron particles during 2008 Beijing Olympic Games using an Aerodyne High-Resolution Aerosol Mass Spectrometer

2010 ◽  
Vol 10 (18) ◽  
pp. 8933-8945 ◽  
Author(s):  
X.-F. Huang ◽  
L.-Y. He ◽  
M. Hu ◽  
M. R. Canagaratna ◽  
Y. Sun ◽  
...  
Keyword(s):  
High Resolution ◽  
Mass Spectrometer ◽  
Olympic Games ◽  
Aerosol Particles ◽  
Organic Aerosol ◽  
Organic Mass ◽  
Aerosol Mass Spectrometer ◽  
Beijing Olympic Games ◽  
Aerosol Mass ◽  
2008 Beijing Olympic Games

Abstract. As part of Campaigns of Air Quality Research in Beijing and Surrounding Region-2008 (CAREBeijing-2008), an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) was deployed in urban Beijing to characterize submicron aerosol particles during the time of 2008 Beijing Olympic Games and Paralympic Games (24 July to 20 September 2008). The campaign mean PM1 mass concentration was 63.1 ± 39.8 μg m−3; the mean composition consisted of organics (37.9%), sulfate (26.7%), ammonium (15.9%), nitrate (15.8%), black carbon (3.1%), and chloride (0.87%). The average size distributions of the species (except BC) were all dominated by an accumulation mode peaking at about 600 nm in vacuum aerodynamic diameter, and organics was characterized by an additional smaller mode extending below 100 nm. Positive Matrix Factorization (PMF) analysis of the high resolution organic mass spectral dataset differentiated the organic aerosol into four components, i.e., hydrocarbon-like (HOA), cooking-related (COA), and two oxygenated organic aerosols (OOA-1 and OOA-2), which on average accounted for 18.1, 24.4, 33.7 and 23.7% of the total organic mass, respectively. The HOA was identified to be closely associated with primary combustion sources, while the COA mass spectrum and diurnal pattern showed similar characteristics to that measured for cooking emissions. The OOA components correspond to aged secondary organic aerosol. Although the two OOA components have similar elemental (O/C, H/C) compositions, they display differences in mass spectra and time series which appear to correlate with the different source regions sampled during the campaign. Back trajectory clustering analysis indicated that the southerly air flows were associated with the highest PM1 pollution during the campaign. Aerosol particles in southern airmasses were especially rich in inorganic and oxidized organic species. Aerosol particles in northern airmasses contained a large fraction of primary HOA and COA species, probably due to stronger influences from local emissions. The lowest concentration levels for all major species were obtained during the Olympic game days (8 to 24 August 2008), possibly due to the effects of both strict emission controls and favorable meteorological conditions.

scholarly journals Elemental analysis of chamber organic aerosol using an aerodyne high-resolution aerosol mass spectrometer

2010 ◽  
Vol 10 (9) ◽  
pp. 4111-4131 ◽  
Author(s):  
P. S. Chhabra ◽  
R. C. Flagan ◽  
J. H. Seinfeld
Keyword(s):  
High Resolution ◽  
Elemental Composition ◽  
Mass Spectrometer ◽  
Organic Aerosol ◽  
Uptake System ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Single Ring ◽  
Spectrometer Data ◽  
Ambient Measurements

Abstract. The elemental composition of laboratory chamber secondary organic aerosol (SOA) from glyoxal uptake, α-pinene ozonolysis, isoprene photooxidation, single-ring aromatic photooxidation, and naphthalene photooxidation is evaluated using Aerodyne high-resolution time-of-flight mass spectrometer data. SOA O/C ratios range from 1.13 for glyoxal uptake experiments to 0.30–0.43 for α-pinene ozonolysis. The elemental composition of α-pinene and naphthalene SOA is also confirmed by offline mass spectrometry. The fraction of organic signal at m/z 44 is generally a good measure of SOA oxygenation for α-pinene/O3, isoprene/high-NOx, and naphthalene SOA systems. The agreement between measured and estimated O/C ratios tends to get closer as the fraction of organic signal at m/z 44 increases. This is in contrast to the glyoxal uptake system, in which m/z 44 substantially underpredicts O/C. Although chamber SOA has generally been considered less oxygenated than ambient SOA, single-ring aromatic- and naphthalene-derived SOA can reach O/C ratios upward of 0.7, well within the range of ambient PMF component OOA, though still not as high as some ambient measurements. The spectra of aromatic and isoprene-high-NOx SOA resemble that of OOA, but the spectrum of glyoxal uptake does not resemble that of any ambient organic aerosol PMF component.

scholarly journals Investigations of primary and secondary particulate matter of different wood combustion appliances with a high-resolution time-of-flight aerosol mass spectrometer

2011 ◽  
Vol 11 (12) ◽  
pp. 5945-5957 ◽  
Author(s):  
M. F. Heringa ◽  
P. F. DeCarlo ◽  
R. Chirico ◽  
T. Tritscher ◽  
J. Dommen ◽  
...  
Keyword(s):  
High Resolution ◽  
Mass Spectrometer ◽  
Organic Aerosol ◽  
Smog Chamber ◽  
Resolution Time ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Wood Burning ◽  
Primary Emissions ◽  
Stable Burning

Abstract. A series of photo-oxidation smog chamber experiments were performed to investigate the primary emissions and secondary aerosol formation from two different log wood burners and a residential pellet burner under different burning conditions: starting and flaming phase. Emissions were sampled from the chimney and injected into the smog chamber leading to primary organic aerosol (POA) concentrations comparable to ambient levels. The composition of the aerosol was measured by an Aerodyne high resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS) and black carbon (BC) instrumentation. The primary emissions were then exposed to xenon light to initiate photo-chemistry and subsequent secondary organic aerosol (SOA) production. After correcting for wall losses, the average increase in organic matter (OM) concentrations by SOA formation for the starting and flaming phase experiments with the two log wood burners was found to be a factor of 4.1±1.4 after five hours of aging. No SOA formation was observed for the stable burning phase of the pellet burner. The startup emissions of the pellet burner showed an increase in OM concentration by a factor of 3.3. Including the measured SOA formation potential, average emission factors of BC+POA+SOA, calculated from CO2 emission, were found to be in the range of 0.04 to 3.9 g/kg wood for the stable burning pellet burner and an old log wood burner during startup respectively. SOA contributed significantly to the ion C2H4O2+ at mass to charge ratio m/z 60, a commonly used marker for primary emissions of wood burning. This contribution at m/z 60 can overcompensate for the degradation of levoglucosan leading to an overestimation of the contribution of wood burning or biomass burning to the total OM. The primary organic emissions from the three different burners showed a wide range in O:C atomic ratio (0.19−0.60) for the starting and flaming conditions, which also increased during aging. Primary wood burning emissions have a rather low relative contribution at m/z 43 (f 43) to the total organic mass spectrum. The non-oxidized fragment C3H7+ has a considerable contribution at m/z 43 for the fresh OA with an increasing contribution of the oxygenated ion C2H3O+ during aging. After five hours of aging, the OA has a rather low C2H3O+ signal for a given CO2+ fraction, possibly indicating a higher ratio of acid to non-acid oxygenated compounds in wood burning OA compared to other oxygenated organic aerosol (OOA).

scholarly journals In situ measurement of PM1 organic aerosol in Beijing winter using a high-resolution aerosol mass spectrometer

2011 ◽  
Vol 57 (7) ◽  
pp. 819-826 ◽  
Author(s):  
Quan Liu ◽  
Yang Sun ◽  
Bo Hu ◽  
ZiRui Liu ◽  
Shimono Akio ◽  
...  
Keyword(s):  
High Resolution ◽  
Mass Spectrometer ◽  
Organic Aerosol ◽  
In Situ Measurement ◽  
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

<p>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.</p><p>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 & 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.</p>

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 A missing source of aerosols in Antarctica – beyond long-range transport, phytoplankton, and photochemistry

2017 ◽  
Vol 17 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Michael R. Giordano ◽  
Lars E. Kalnajs ◽  
Anita Avery ◽  
J. Douglas Goetz ◽  
Sean M. Davis ◽  
...  
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Real Time ◽  
Mass Spectrometer ◽  
Formation Mechanisms ◽  
Second Phase ◽  
Austral Spring ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
The Antarctic

Abstract. Understanding the sources and evolution of aerosols is crucial for constraining the impacts that aerosols have on a global scale. An unanswered question in atmospheric science is the source and evolution of the Antarctic aerosol population. Previous work over the continent has primarily utilized low temporal resolution aerosol filters to answer questions about the chemical composition of Antarctic aerosols. Bulk aerosol sampling has been useful in identifying seasonal cycles in the aerosol populations, especially in populations that have been attributed to Southern Ocean phytoplankton emissions. However, real-time, high-resolution chemical composition data are necessary to identify the mechanisms and exact timing of changes in the Antarctic aerosol. The recent 2ODIAC (2-Season Ozone Depletion and Interaction with Aerosols Campaign) field campaign saw the first ever deployment of a real-time, high-resolution aerosol mass spectrometer (SP-AMS – soot particle aerosol mass spectrometer – or AMS) to the continent. Data obtained from the AMS, and a suite of other aerosol, gas-phase, and meteorological instruments, are presented here. In particular, this paper focuses on the aerosol population over coastal Antarctica and the evolution of that population in austral spring. Results indicate that there exists a sulfate mode in Antarctica that is externally mixed with a mass mode vacuum aerodynamic diameter of 250 nm. Springtime increases in sulfate aerosol are observed and attributed to biogenic sources, in agreement with previous research identifying phytoplankton activity as the source of the aerosol. Furthermore, the total Antarctic aerosol population is shown to undergo three distinct phases during the winter to summer transition. The first phase is dominated by highly aged sulfate particles comprising the majority of the aerosol mass at low wind speed. The second phase, previously unidentified, is the generation of a sub-250 nm aerosol population of unknown composition. The second phase appears as a transitional phase during the extended polar sunrise. The third phase is marked by an increased importance of biogenically derived sulfate to the total aerosol population (photolysis of dimethyl sulfate and methanesulfonic acid (DMS and MSA)). The increased importance of MSA is identified both through the direct, real-time measurement of aerosol MSA and through the use of positive matrix factorization on the sulfur-containing ions in the high-resolution mass-spectral data. Given the importance of sub-250 nm particles, the aforementioned second phase suggests that early austral spring is the season where new particle formation mechanisms are likely to have the largest contribution to the aerosol population in Antarctica.

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