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.

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 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 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 Development of an Aerosol Mass Spectrometer for Size and Composition Analysis of Submicron Particles

2000 ◽  
Vol 33 (1-2) ◽  
pp. 49-70 ◽  
Author(s):  
John T. Jayne ◽  
Danna C. Leard ◽  
Xuefeng Zhang ◽  
Paul Davidovits ◽  
Kenneth A. Smith ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Submicron Particles ◽  
Composition Analysis ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass

scholarly journals Summertime aerosol volatility measurements in Beijing, China

2019 ◽  
Author(s):  
Weiqi Xu ◽  
Conghui Xie ◽  
Eleni Karnezi ◽  
Qi Zhang ◽  
Junfeng Wang ◽  
...  
Keyword(s):  
Aerosol Particles ◽  
High Mass ◽  
Transfer Model ◽  
Organic Nitrates ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Metallic Salts ◽  
Volatile Organic ◽  
Effective Saturation ◽  
Beijing China

Abstract. Volatility plays a key role in affecting mass concentrations and lifetime of aerosol particles in the atmosphere, yet our knowledge of aerosol volatility in relatively polluted environment, e.g., north China remains poor. Here aerosol volatility in Beijing in summer 2017 and 2018 was measured using a thermodenuder (TD) coupled with an Aerodyne high-resolution aerosol mass spectrometer (AMS) and a soot particle AMS. Our results showed overall similar thermograms for most non-refractory aerosol species compared with those reported in previous studies. However, high mass fraction remaining and NO+/NO2+ ratio for chloride and nitrate, respectively above 200 °C indicated the presence of considerable metallic salts and organic nitrates in Beijing. The volatility distributions of organic aerosol (OA) and four OA factors that were resolved from positive matrix factorization were estimated using a mass transfer model. The ambient OA comprised mainly semi-volatile organic compounds (SVOC, 63 %) with an average effective saturation concentration (C*) of 0.55 µg m−3, suggesting overall more volatile properties than OA in megacities of Europe and US. Further analysis showed that the freshly oxidized secondary OA (LO-OOA) was the most volatile OA factor (SVOC = 70 %) followed by hydrocarbon-like OA (HOA). In contrast, the volatility of more oxidized SOA (MO-OOA) was comparable to that of cooking OA with SVOC on average accounting for 60.2 %. We also compared the volatility of ambient and black carbon–containing OA. Our results showed that the BC-containing primary OA (POA) was much more volatile than ambient POA (C*= 0.69 µg m−3 vs. 0.37 µg m−3), while the BC-containing SOA was much less volatile, highlighting the very different composition and properties between BC-containing and ambient aerosol particles.

scholarly journals Size-resolved aerosol composition and link to hygroscopicity at a forested site in Colorado

2013 ◽  
Vol 13 (9) ◽  
pp. 23817-23843 ◽  
Author(s):  
E. J. T. Levin ◽  
A. J. Prenni ◽  
B. Palm ◽  
D. Day ◽  
P. Campuzano-Jost ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Cloud Condensation Nuclei ◽  
Cloud Droplet ◽  
Large Mass ◽  
Aerosol Composition ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Mass Fractions ◽  
Aerosol Hygroscopicity ◽  
Aerosol Chemical Composition

Abstract. Aerosol hygroscopicity describes the ability of a particle to take up water and form a cloud droplet. Modeling studies have shown sensitivity of precipitation-producing cloud systems to the availability of aerosol particles capable of serving as cloud condensation nuclei (CCN), and hygroscopicity is a key parameter controlling the number of available CCN. Continental aerosol is typically assumed to have a representative hygroscopicity parameter, κ, of 0.3; however, in remote locations this value can be lower due to relatively large mass fractions of organic components. To further our understanding of aerosol properties in remote areas, we measured size-resolved aerosol chemical composition and hygroscopicity in a forested, mountainous site in Colorado during the six-week BEACHON-RoMBAS campaign. This campaign followed a year-long measurement period at this site, and results from the intensive campaign shed light on the previously reported seasonal cycle in aerosol hygroscopicity. New particle formation events were observed routinely at this site and nucleation mode composition measurements indicated that the newly formed particles were predominantly organic. These events likely contribute to the dominance of organic species at smaller sizes, where aerosol organic mass fractions of non-refractory components were between 70–90%. Corresponding aerosol hygroscopicity was observed to range from κ = 0.15–0.22, with hygroscopicity increasing with particle size. Aerosol chemical composition measured by an Aerosol Mass Spectrometer and calculated from hygroscopicity measurements agreed very well during the intensive study with an assumed value of κorg = 0.13 resulting in the best agreement.

Characterization of aerosol composition, concentrations, and sources at Baengnyeong Island, Korea using an aerosol mass spectrometer

2015 ◽  
Vol 120 ◽  
pp. 297-306 ◽  
Author(s):  
Taehyoung Lee ◽  
Jinsoo Choi ◽  
Gangwoong Lee ◽  
Junyoung Ahn ◽  
Jin Soo Park ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Aerosol Composition ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass
Sign in / Sign up

Export Citation Format

Share Document