scholarly journals Thermo-Optical and Particle Number Size Distribution Characteristics of Smoldering Smoke from Biomass Burning

2019 ◽  
Vol 9 (23) ◽  
pp. 5259
Author(s):  
Feng Wang ◽  
Qixing Zhang ◽  
Xuezhe Xu ◽  
Weixiong Zhao ◽  
Yongming Zhang ◽  
...  
Keyword(s):  
Size Distribution ◽  
Biomass Burning ◽  
Lognormal Distribution ◽  
Particle Number ◽  
Extinction Coefficients ◽  
Nucleation Mode ◽  
Number Size Distribution ◽  
Particle Number Size Distribution ◽  
The Relationship ◽  
Aitken Mode

Controlled laboratory combustion experiments were conducted in the fire test room to mimic freshly emitted smoldering smoke of biomass burning in China. The biomass components were determined by ultimate analysis and proximate analysis before experiments. The particle number size distribution (PNSD) between 5 and 1000 nm of smoke was measured by a high sampling frequency size spectrometer. A cavity-enhanced aerosol albedometer with wavelength of 532 nm was used to measure scattering coefficients, extinction coefficients, and single scattering albedo (SSA) of smoldering smoke. The PNSDs of smoldering smoke from the burning of agricultural straw could be fitted with a bimodal lognormal distribution as modes around 10 nm (nucleation mode) and 60 nm (Aitken mode). The PNSDs of wood sawdust could be fitted with a trimodal lognormal distribution, while the two modes were in nucleation mode, and one was in Aitken mode. The bulk optical properties (scattering and extinction coefficients) of smoldering smoke had strong correlations with particle number concentrations of sizes bigger than 100 nm. The correlation between SSA and fixed carbon (FC) was strong (the correlation coefficient is 0.89), while the correlation between SSA and volatile matter (VM) or ash was weak. The relationship between SSA and N (or S) showed a positive correlation, while that of SSA and C showed a negative correlation. The relationship between SSA and VM/FC (or N) showed a strong linear relationship (r2 > 0.8). This paper could improve understanding of the relationship between the optical and particle size distribution properties of smoke from biomass burning and the components of biomass materials under similar combustion conditions.

scholarly journals Measurement of nonvolatile particle number size distribution

2016 ◽  
Vol 9 (1) ◽  
pp. 103-114 ◽  
Author(s):  
G. I. Gkatzelis ◽  
D. K. Papanastasiou ◽  
K. Florou ◽  
C. Kaltsonoudis ◽  
E. Louvaris ◽  
...  
Keyword(s):  
Size Distribution ◽  
Black Carbon ◽  
Biomass Burning ◽  
Particle Number ◽  
Number Concentration ◽  
Experimental Methodology ◽  
Particle Number Concentration ◽  
Scanning Mobility Particle Sizer ◽  
Number Size Distribution ◽  
Particle Sizer

Abstract. An experimental methodology was developed to measure the nonvolatile particle number concentration using a thermodenuder (TD). The TD was coupled with a high-resolution time-of-flight aerosol mass spectrometer, measuring the chemical composition and mass size distribution of the submicrometer aerosol and a scanning mobility particle sizer (SMPS) that provided the number size distribution of the aerosol in the range from 10 to 500 nm. The method was evaluated with a set of smog chamber experiments and achieved almost complete evaporation (> 98 %) of secondary organic as well as freshly nucleated particles, using a TD temperature of 400 °C and a centerline residence time of 15 s. This experimental approach was applied in a winter field campaign in Athens and provided a direct measurement of number concentration and size distribution for particles emitted from major pollution sources. During periods in which the contribution of biomass burning sources was dominant, more than 80 % of particle number concentration remained after passing through the thermodenuder, suggesting that nearly all biomass burning particles had a nonvolatile core. These remaining particles consisted mostly of black carbon (60 % mass contribution) and organic aerosol (OA; 40 %). Organics that had not evaporated through the TD were mostly biomass burning OA (BBOA) and oxygenated OA (OOA) as determined from AMS source apportionment analysis. For periods during which traffic contribution was dominant 50–60 % of the particles had a nonvolatile core while the rest evaporated at 400 °C. The remaining particle mass consisted mostly of black carbon with an 80 % contribution, while OA was responsible for another 15–20 %. Organics were mostly hydrocarbon-like OA (HOA) and OOA. These results suggest that even at 400 °C some fraction of the OA does not evaporate from particles emitted from common combustion processes, such as biomass burning and car engines, indicating that a fraction of this type of OA is of extremely low volatility.

scholarly journals The effect of local sources on aerosol particle number size distribution, concentrations and fluxes in Helsinki, Finland

Tellus B ◽  
2013 ◽  
Vol 65 (1) ◽  
pp. 19786 ◽  
Author(s):  
Giovanna Ripamonti ◽  
Leena Järvi ◽  
Bjarke Mølgaard ◽  
Tareq Hussein ◽  
Annika Nordbo ◽  
...  
Keyword(s):  
Size Distribution ◽  
Aerosol Particle ◽  
Particle Number ◽  
Number Size Distribution ◽  
Local Sources ◽  
Particle Number Size Distribution

scholarly journals Spatio-temporal variability and principal components of the particle number size distribution in an urban atmosphere

2009 ◽  
Vol 9 (9) ◽  
pp. 3163-3195 ◽  
Author(s):  
F. Costabile ◽  
W. Birmili ◽  
S. Klose ◽  
T. Tuch ◽  
B. Wehner ◽  
...  
Keyword(s):  
Size Distribution ◽  
Particle Number ◽  
Aerosol Particles ◽  
Urban Traffic ◽  
Urban Atmosphere ◽  
Urban Aerosol ◽  
Number Size Distribution ◽  
Spatio Temporal ◽  
20 Nm ◽  
Aitken Mode

Abstract. A correct description of fine (diameter <1 μm) and ultrafine (<0.1 μm) aerosol particles in urban areas is of interest for particle exposure assessment but also basic atmospheric research. We examined the spatio-temporal variability of atmospheric aerosol particles (size range 3–800 nm) using concurrent number size distribution measurements at a maximum of eight observation sites in and around Leipzig, a city in Central Europe. Two main experiments were conducted with different time span and number of observation sites (2 years at 3 sites; 1 month at 8 sites). A general observation was that the particle number size distribution varied in time and space in a complex fashion as a result of interaction between local and far-range sources, and the meteorological conditions. To identify statistically independent factors in the urban aerosol, different runs of principal component (PC) analysis were conducted encompassing aerosol, gas phase, and meteorological parameters from the multiple sites. Several of the resulting PCs, outstanding with respect to their temporal persistence and spatial coverage, could be associated with aerosol particle modes: a first accumulation mode ("droplet mode", 300–800 nm), considered to be the result of liquid phase processes and far-range transport; a second accumulation mode (centered around diameters 90–250 nm), considered to result from primary emissions as well as aging through condensation and coagulation; an Aitken mode (30–200 nm) linked to urban traffic emissions in addition to an urban and a rural Aitken mode; a nucleation mode (5–20 nm) linked to urban traffic emissions; nucleation modes (3–20 nm) linked to photochemically induced particle formation; an aged nucleation mode (10–50 nm). Additional PCs represented only local sources at a single site, or infrequent phenomena. In summary, the analysis of size distributions of high time and size resolution yielded a surprising wealth of statistical aerosol components occurring in the urban atmosphere over one single city. A paradigm on the behaviour of sub-μm urban aerosol particles is proposed, with recommendations how to efficiently monitor individual sub-fractions across an entire city.

Development of particle number size distribution near a major road in Helsinki during an episodic inversion situation

2007 ◽  
Vol 41 (8) ◽  
pp. 1759-1767 ◽  
Author(s):  
Veli-Matti Kerminen ◽  
Tuomo A. Pakkanen ◽  
Timo Mäkelä ◽  
Risto E. Hillamo ◽  
Markus Sillanpää ◽  
...  
Keyword(s):  
Size Distribution ◽  
Particle Number ◽  
Major Road ◽  
Number Size Distribution ◽  
Particle Number Size Distribution

scholarly journals Vertical and horizontal variation of aerosol number size distribution in the boreal environment

2016 ◽  
Author(s):  
Riikka Väänänen ◽  
Radovan Krejci ◽  
Hanna E. Manninen ◽  
Antti Manninen ◽  
Janne Lampilahti ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Size Distribution ◽  
Planetary Boundary Layer ◽  
Particle Number ◽  
Ground Level ◽  
Number Concentration ◽  
Field Station ◽  
Airborne Measurements ◽  
Number Size Distribution ◽  
Particle Number Size Distribution

Abstract. This study explores the vertical and horizontal variability of the particle number size distribution from two flight measurements campaigns over a boreal forest in Hyytiälä, Finland during May–June 2013 and March–April 2014, respectively. Our other aims were to study the spatial extent of new particle formation events and to compare the airborne observation with the ground measurements from the SMEAR II (Station for Measuring Ecosystem-Atmosphere Relations) field station located in Hyytiälä. The airborne measurements extended vertically 3.8 km and horizontally 30 km from the station. A Cessna 172 aircraft was used as a measurement platform. The measured parameters included the particle number concentration (> 3 nm) and particle number size distribution (10–400 nm). The airborne data used in this study were equal to 111 flight hours. The measurements showed that despite local fluctuations there was a good agreement between the on-ground and airborne measurements inside the planetary boundary layer. On median, the airborne total number concentration was found to be 10 % larger than at the ground level. The seasonal and meteorological differences between the campaigns were reflected in aerosol properties. NPF days showed areas of intensified NPF on a scale from kilometres up to couple of tens of kilometres in the planetary boundary layer. NPF was also observed frequently in the free troposphere.

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