The effects of physical and chemical characteristics of aerosol number concentration on scattering coefficients in Nanjing, China: Insights from a single particle aerosol mass spectrometer

2021 ◽  
Vol 250 ◽  
pp. 105382
Author(s):  
Jianan Zou ◽  
Junlin An ◽  
Qimin Cao ◽  
Honglei Wang ◽  
Junxiu Wang ◽  
...  
2013 ◽  
Vol 40 (6) ◽  
pp. 936-939
Author(s):  
Mei LI ◽  
Jun-Guo DONG ◽  
Zheng-Xu HUANG ◽  
Lei LI ◽  
Wei GAO ◽  
...  

2017 ◽  
Vol 10 (10) ◽  
pp. 3801-3820 ◽  
Author(s):  
Jin Liao ◽  
Charles A. Brock ◽  
Daniel M. Murphy ◽  
Donna T. Sueper ◽  
André Welti ◽  
...  

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.


2016 ◽  
Vol 16 (4) ◽  
pp. 2631-2640 ◽  
Author(s):  
Guohua Zhang ◽  
Xinhui Bi ◽  
Ning Qiu ◽  
Bingxue Han ◽  
Qinhao Lin ◽  
...  

Abstract. Knowledge on the microphysical properties of atmospheric aerosols is essential to better evaluate their radiative forcing. This paper presents an estimate of the real part of the refractive indices (n) and effective densities (ρeff) of chemically segregated atmospheric aerosols in Guangzhou, China. Vacuum aerodynamic diameter, chemical compositions, and light-scattering intensities of individual particles were simultaneously measured by a single-particle aerosol mass spectrometer (SPAMS) during the fall of 2012. On the basis of Mie theory, n at a wavelength of 532 nm and ρeff were estimated for 17 particle types in four categories: organics (OC), elemental carbon (EC), internally mixed EC and OC (ECOC), and Metal-rich. The results indicate the presence of spherical or nearly spherical shapes for the majority of particle types, whose partial scattering cross-section versus sizes were well fitted to Mie theoretical modeling results. While sharing n in a narrow range (1.47–1.53), majority of particle types exhibited a wide range of ρeff (0.87–1.51 g cm−3). The OC group is associated with the lowest ρeff (0.87–1.07 g cm−3), and the Metal-rich group with the highest ones (1.29–1.51 g cm−3). It is noteworthy that a specific EC type exhibits a complex scattering curve versus size due to the presence of both compact and irregularly shaped particles. Overall, the results on the detailed relationship between physical and chemical properties benefits future research on the impact of aerosols on visibility and climate.


2012 ◽  
Vol 40 (6) ◽  
pp. 936-939 ◽  
Author(s):  
Mei LI ◽  
Jun-Guo DONG ◽  
Zheng-Xu HUANG ◽  
Lei LI ◽  
Wei GAO ◽  
...  

Author(s):  
L. Zhao ◽  
C. Yang

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%.


2013 ◽  
Vol 6 (3) ◽  
pp. 5653-5691 ◽  
Author(s):  
F. Freutel ◽  
F. Drewnick ◽  
J. Schneider ◽  
T. Klimach ◽  
S. Borrmann

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.


2015 ◽  
Vol 15 (4) ◽  
pp. 1823-1841 ◽  
Author(s):  
A. K. Y. Lee ◽  
M. D. Willis ◽  
R. M. Healy ◽  
T. B. Onasch ◽  
J. P. D. Abbatt

Abstract. Understanding the impact of atmospheric black carbon (BC)-containing particles on human health and radiative forcing requires knowledge of the mixing state of BC, including the characteristics of the materials with which it is internally mixed. In this study, we examine the mixing state of refractory BC (rBC) and other aerosol components in an urban environment (downtown Toronto) utilizing the Aerodyne soot particle aerosol mass spectrometer equipped with a light scattering module (LS-SP-AMS). k-means cluster analysis was used to classify single particle mass spectra into chemically distinct groups. One resultant particle class is dominated by rBC mass spectral signals (C1+ to C5+) while the organic signals fall into a few major particle classes identified as hydrocarbon-like organic aerosol (HOA), oxygenated organic aerosol (OOA), and cooking emission organic aerosol (COA). A gradual mixing is observed with small rBC particles only thinly coated by HOA (~ 28% by mass on average), while over 90% of the HOA-rich particles did not contain detectable amounts of rBC. Most of the particles classified into other inorganic and organic particle classes were not significantly associated with rBC. The single particle results also suggest that HOA and COA emitted from anthropogenic sources were likely major contributors to organic-rich particles with vacuum aerodynamic diameter (dva) ranging from ~ 200 to 400 nm. The similar temporal profiles and mass spectral features of the organic classes identified by cluster analysis and the factors from a positive matrix factorization (PMF) analysis of the ensemble aerosol data set validate the interpretation of the PMF results.


2013 ◽  
Vol 6 (11) ◽  
pp. 3131-3145 ◽  
Author(s):  
F. Freutel ◽  
F. Drewnick ◽  
J. Schneider ◽  
T. Klimach ◽  
S. Borrmann

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.


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