scholarly journals Aerosol physicochemical properties and implication for visibility during an intense haze episode during winter in Beijing

2014 ◽  
Vol 14 (16) ◽  
pp. 23375-23413 ◽  
Author(s):  
Y. H. Wang ◽  
Z. R. Liu ◽  
J. K. Zhang ◽  
B. Hu ◽  
D. S. Ji ◽  
...  
Keyword(s):  
Light Scattering ◽  
Particle Growth ◽  
Submicron Particles ◽  
Aerosol Mass Spectrometer ◽  
Average Mass ◽  
Submicron Aerosol ◽  
Aerosol Mass ◽  
Synoptic Conditions ◽  
Haze Episode ◽  
Pm2.5 And Pm10

Abstract. The evolution of physical, chemical and optical properties of urban aerosol particles was characterized during an extreme haze episode in Beijing, PRC from 24 January through 31 January 2013 based on in-situ measurements. The average mass concentrations of PM1, PM2.5 and PM10 were 99 ± 67 μg m−3 (average ± stdev), 188 ± 128 μg m−3 and 265 ± 157 μg m−3, respectively. A significant increase in PM1−2.5 fraction was observed during the most heavily polluted periods. The average scattering coefficient (λ = 550 nm) was 877 ± 624 M m−1. An increasing relative amount of coarse particles can be deduced from the variations of backscattering ratios, asymmetry parameter and scattering Ångström exponent. Particle number size distributions between 14 nm and 2500 nm diameter showed high number concentrations, particularly in the nucleation mode and accumulation modes. Size-resolved chemical composition of submicron aerosol from a High Resolution-ToF-Aerosol Mass Spectrometer showed that the mass concentration of organic, sulfate, nitrate, ammonium and chlorine mainly resided on 500 nm to 800 nm (vacuum diameter) particles, and sulfate and ammonium contributed most to particle growth during the most heavily polluted day (28 January). Increasing relative humidity and stable synoptic conditions on 28 January combined with heavy pollution, lead to enhanced water uptake by the hygroscopic submicron particles and formation of secondary aerosol, maybe the main reasons for the severity of the haze episode. Light scattering apportionment showed that organic, ammonium sulfate, ammonium nitrate and ammonium chloride compounds contributed to light scattering fractions of 57%, 23%, 10% and 10%, respectively. This study indicated that the organic component in submicron aerosol plays an important role in visibility degradation in this haze episode in and around Beijing.

scholarly journals Aerosol physicochemical properties and implications for visibility during an intense haze episode during winter in Beijing

2015 ◽  
Vol 15 (6) ◽  
pp. 3205-3215 ◽  
Author(s):  
Y. H. Wang ◽  
Z. R. Liu ◽  
J. K. Zhang ◽  
B. Hu ◽  
D. S. Ji ◽  
...  
Keyword(s):  
Light Scattering ◽  
Particle Growth ◽  
Submicron Particles ◽  
Average Mass ◽  
Submicron Aerosol ◽  
Organic Sulfate ◽  
Synoptic Conditions ◽  
Haze Episode ◽  
Pm2.5 And Pm10 ◽  
Mass Concentrations

Abstract. The evolution of physical, chemical and optical properties of urban aerosol particles was characterized during an extreme haze episode in Beijing, PRC, from 24 through 31 January 2013 based on in situ measurements. The average mass concentrations of PM1, PM2.5 and PM10 were 99 ± 67 μg m−3 (average ± SD), 188 ± 128 μg m−3 and 265 ± 157 μg m−3, respectively. A significant increase in PM1-2.5 fraction was observed during the most heavily polluted period. The average scattering coefficient at 550 nm was 877 ± 624 Mm−1. An increasing relative amount of coarse particles can be deduced from the variations of backscattering ratios, asymmetry parameter and scattering Ångström exponent. Particle number-size distributions between 14 and 2500 nm diameter showed high number concentrations, particularly in the nucleation mode and accumulation mode. Size-resolved chemical composition of submicron aerosol from a high-resolution time-of-flight aerosol mass spectrometer showed that the mass concentrations of organic, sulfate, nitrate, ammonium and chlorine mainly resided on particles between 500 and 800 nm (vacuum diameter), and nitrate and ammonium contributed greatly to particle growth during the heavily polluted day (28 January). Increasing relative humidity and stable synoptic conditions on 28 January combined with heavy pollution on 28 January, leading to enhanced water uptake by the hygroscopic submicron particles and formation of secondary aerosol, which might be the main reasons for the severity of the haze episode. Light-scattering apportionment showed that organic, sulfate, ammonium nitrate and ammonium chloride compounds contributed to light-scattering fractions of 54, 24, 12 and 10%, respectively. This study indicated that the organic component in submicron aerosol played an important role in visibility degradation during the haze episode in Beijing.

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 CHEMICAL COMPOSITION OF AEROSOLS IN THE WEST COAST OF TAIWAN STRAIT, CHINA

2019 ◽  
Vol XLII-3/W9 ◽  
pp. 233-237
Author(s):  
L. Zhao ◽  
C. Yang
Keyword(s):  
Chemical Composition ◽  
Mass Spectrometer ◽  
Single Particle ◽  
Inorganic Ions ◽  
Water Soluble ◽  
Ion Concentration ◽  
Aerosol Mass Spectrometer ◽  
Average Mass ◽  
Inorganic Ion ◽  
Aerosol Mass

Abstract. The chemical composition of aerosols was investigated using regular environmental air quality observation, a single particle aerosol mass spectrometer (SPAMS 0515) and an ambient ion monitor (URG 9000D) in Xiamen in 2018. The results showed that the annual average mass concentrations of PM2.5 was 22 μm/m3, and concentrations of water-soluble inorganic ions was 9.94 μm/m3 which accounted for 45.2% of PM2.5. SO42−, NO3− and NH4+ were main components of secondary reactions which contributed more than 77 percent of water-soluble inorganic ion concentration. As a coastal city, Cl− and Na+ contributed 13.9 percent of water-soluble inorganic ion concentration. Based on single particle aerosol mass spectrometer analysing, mobile sources emission was the most important sources of particle matter which contributed over 30%.

scholarly journals Quantitative single particle analysis with the Aerodyne aerosol mass spectrometer: development of a new classification algorithm and its application to field data

2013 ◽  
Vol 6 (3) ◽  
pp. 5653-5691 ◽  
Author(s):  
F. Freutel ◽  
F. Drewnick ◽  
J. Schneider ◽  
T. Klimach ◽  
S. Borrmann
Keyword(s):  
Mass Spectrometer ◽  
Single Particle ◽  
Field Data ◽  
Classification Algorithm ◽  
Particle Mass ◽  
Submicron Particles ◽  
Particle Analysis ◽  
Mixing State ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass

Abstract. Single particle mass spectrometry has proven a valuable tool for gaining information on the mixing state of aerosol particles. With the Aerodyne aerosol mass spectrometer (AMS) equipped with a light scattering probe, non-refractory components of submicron particles with diameters larger than about 300 nm can even be quantified on a single particle basis. Here, we present a new method for the analysis of AMS single particle mass spectra. The developed algorithm classifies the particles according to their components (e.g., sulphate, nitrate, different types of organics) and simultaneously provides quantitative information about the composition of the single particles. This classification algorithm was validated by applying it to data acquired in laboratory experiments with particles of known composition, and applied to field data acquired during the MEGAPOLI summer campaign (July 2009) in Paris. As shown, it is not only possible to directly measure the mixing state of atmospheric particles, but also to directly observe repartitioning of semi-volatile species between gas and particle phase during the course of the day.

scholarly journals Characterization and source apportionment of submicron aerosol with aerosol mass spectrometer during the PRIDE-PRD 2006 campaign

2011 ◽  
Vol 11 (14) ◽  
pp. 6911-6929 ◽  
Author(s):  
R. Xiao ◽  
N. Takegawa ◽  
M. Zheng ◽  
Y. Kondo ◽  
Y. Miyazaki ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Urban Areas ◽  
Organic Aerosol ◽  
Water Soluble ◽  
Aerosol Formation ◽  
Aerosol Mass Spectrometer ◽  
Air Masses ◽  
Submicron Aerosol ◽  
Pmf Model ◽  
Aerosol Mass

Abstract. Size-resolved chemical compositions of non-refractory submicron aerosol were measured using an Aerodyne quadrupole aerosol mass spectrometer (Q-AMS) at the rural site Back Garden (BG), located ~50 km northwest of Guangzhou in July 2006. This paper characterized the submicron aerosol particles of regional air pollution in Pearl River Delta (PRD) in the southern China. Organics and sulfate dominated the submicron aerosol compositions, with average mass concentrations of 11.8 ± 8.4 μg m−3 and 13.5 ± 8.7 μg m−3, respectively. Unlike other air masses, the air masses originated from Southeast-South and passing through the PRD urban areas exhibited distinct bimodal size distribution characteristics for both organics and sulfate: the first mode peaked at vacuum aerodynamic diameters (Dva) ∼200 nm and the second mode occurred at Dva from 300–700 nm. With the information from AMS, it was found from this study that the first mode of organics in PRD regional air masses was contributed by both secondary organic aerosol formation and combustion-related emissions, which is different from most findings in other urban areas (first mode of organics primarily from combustion-related emissions). The analysis of AMS mass spectra data by positive matrix factorization (PMF) model identified three sources of submicron organic aerosol including hydrocarbon-like organic aerosol (HOA), low volatility oxygenated organic aerosol (LV-OOA) and semi-volatile oxygenated organic aerosol (SV-OOA). The strong correlation between HOA and EC indicated primary combustion emissions as the major source of HOA while a close correlation between SV-OOA and semi-volatile secondary species nitrate as well as between LV-OOA and nonvolatile secondary species sulfate suggested secondary aerosol formation as the major source of SV-OOA and LV-OOA at the BG site. However, LV-OOA was more aged than SV-OOA as its spectra was highly correlated with the reference spectra of fulvic acid, an indicator of aged and oxygenated aerosol. The origin of HOA and OOA (the sum of LV-OOA and SV-OOA) has been further confirmed by the statistics that primary organic carbon (POC) and secondary organic carbon (SOC), estimated by the EC tracer method, were closely correlated with HOA and OOA, respectively. The results of the EC tracer method and of the PMF model revealed that primary organic aerosol (POA) constituted ~34–47 % of OA mass and secondary organic aerosol (SOA) constituted ~53–66 % of regional organic aerosol in PRD during summer season. The presence of abundant SOA was consistent with water soluble organic carbon (WSOC) results (accounting for ~60 % of OC on average) by Miyazaki et al. (2009) for the same campaign. OOA correlated well with WSOC at the BG site, indicating that most OOA were water soluble. More specifically, approximately 86 % of LV-OOA and 61 % of SV-OOA were estimated as water soluble species on the basis of carbon content comparison.

scholarly journals Quantitative single-particle analysis with the Aerodyne aerosol mass spectrometer: development of a new classification algorithm and its application to field data

2013 ◽  
Vol 6 (11) ◽  
pp. 3131-3145 ◽  
Author(s):  
F. Freutel ◽  
F. Drewnick ◽  
J. Schneider ◽  
T. Klimach ◽  
S. Borrmann
Keyword(s):  
Mass Spectrometer ◽  
Single Particle ◽  
Field Data ◽  
Classification Algorithm ◽  
Particle Mass ◽  
Submicron Particles ◽  
Particle Analysis ◽  
Mixing State ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass

Abstract. Single-particle mass spectrometry has proven a valuable tool for gaining information on the mixing state of aerosol particles. With the Aerodyne aerosol mass spectrometer (AMS) equipped with a light-scattering probe, non-refractory components of submicron particles with diameters larger than about 300 nm can even be quantified on a single-particle basis. Here, we present a new method for the analysis of AMS single-particle mass spectra. The developed algorithm classifies the particles according to their components (e.g. sulphate, nitrate, different types of organics) and simultaneously provides quantitative information about the composition of the single particles. This classification algorithm was validated by applying it to data acquired in laboratory experiments with particles of known composition, and applied to field data acquired during the MEGAPOLI summer campaign (July 2009) in Paris. As shown, it is not only possible to directly measure the mixing state of atmospheric particles, but also to directly observe repartitioning of semi-volatile species between gas and particle phase during the course of the day.

scholarly journals Vertical Profiles of Aerosol Composition over Beijing, China: Analysis of In Situ Aircraft Measurements

2019 ◽  
Vol 76 (1) ◽  
pp. 231-245 ◽  
Author(s):  
Quan Liu ◽  
Jiannong Quan ◽  
Xingcan Jia ◽  
Zhaobin Sun ◽  
Xia Li ◽  
...  
Keyword(s):  
Mass Fraction ◽  
Submicron Particles ◽  
Molar Ratio ◽  
Vertical Diffusion ◽  
Aerosol Composition ◽  
Aerosol Mass Spectrometer ◽  
Complex Processes ◽  
Aerosol Mass ◽  
Composition Profiles ◽  
Beijing China

Abstract Aerosol samples were collected over Beijing, China, during several flights in November 2011. Aerosol composition of nonrefractory submicron particles (NR-PM1) was measured by an Aerodyne compact time-of-flight aerosol mass spectrometer (C-ToF-AMS). This measurement on the aircraft provided vertical distribution of aerosol species over Beijing, including sulfate (SO4), nitrate (NO3), ammonium (NH4), chloride (Chl), and organic aerosols [OA; hydrocarbon-like OA (HOA) and oxygenated OA (OOA)]. The observations showed that aerosol compositions varied drastically with altitude, especially near the top of the planetary boundary layer (PBL). On average, organics (34%) and nitrate (32%) were dominant components in the PBL, followed by ammonium (15%), sulfate (14%), and chloride (4%); in the free troposphere (FT), sulfate (34%) and organics (28%) were dominant components, followed by ammonium (20%), nitrate (19%), and chloride (1%). The dominant OA species was primarily HOA in the PBL but changed to OOA in the FT. For sulfate, nitrate, and ammonium, the sulfate mass fraction increased from the PBL to the FT, nitrate mass fraction decreased, and ammonium remained relatively constant. Analysis of the sulfate-to-nitrate molar ratio further indicated that this ratio was usually less than one in the FT but larger than one in the PBL. Further analysis revealed that the vertical aerosol composition profiles were influenced by complex processes, including PBL structure, regional transportation, emission variation, and the aging process of aerosols and gaseous precursors during vertical diffusion.

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