Lower order representations of evolving particle size distributions for rapid gas-particle mass transfer simulations during electrostatic precipitation

Abstract. In-situ measurements of vertically resolved particle size distributions based on a tethered balloon system were carried out for the first time in the highland city of Lhasa over the Tibetan Plateau in summer 2020, using portable optical counters for the size range of 0.124~32 μm. The vertical structure of 112 aerosol profiles was found to be largely shaped by the evolution of the boundary layer (BL), with a nearly uniform distribution of aerosols within the daytime mixing layer and a sharp decline with the height in the shallow nocturnal boundary layer. During the campaign, the average mass concentration of particulate matters smaller than 2.5 μm in aerodynamic diameter (PM2.5) within the BL was around 3 μg m−3, almost four times of the amount in the free troposphere (FT), which was rarely affected by surface anthropogenic emissions. Though there was a lower level of particle mass in the residual layer (RL) than in the BL, a similarity in particle mass size distributions (PMSDs) suggested that particles in the RL might be of the same origin as particles in the BL. This was also in consistence with the source apportionment analysis based on the PMSDs. Three distinct modes were observed in the PMSDs for the BL and the RL. One mode was exclusively coarse particles up to roughly 15 μm and peaked around 5 μm. More than 50 % of total particle mass was often contributed by coarse mode particles in this area, which was thought to be associated with local dust resuspension. The mode peaking over 0.5~0.7 μm was representative of biomass burning on religious holidays and was found to be most pronounced on holiday mornings. The contribution from the religious burning factor rose from about 25 % on non-holidays to nearly 50 % on holiday mornings. The mode dominated by particles smaller than 0.3 μm was thought to be associated with combustion related emissions and/or secondary aerosol formation. In the FT coarse mode particles only accounted for less than 10 % of the total mass and particles larger than 5 μm were negligible. The predominant submicron particles in the FT might be related to secondary aerosol formation and the aging of existed particles. To give a full picture of aerosol physical and chemical properties and better understand the origin and impacts of aerosols in this area, intensive field campaigns involving measurements of vertically resolved aerosol chemical compositions in different seasons would be much encouraged in the future.

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Experimental Research on the Mass Transfer and Flow Properties of Water Inrush in Completely Weathered Granite Under Different Particle Size Distributions

Rock Mechanics and Rock Engineering ◽

10.1007/s00603-018-1719-3 ◽

2019 ◽

Vol 52 (7) ◽

pp. 2141-2153 ◽

Cited By ~ 8

Author(s):

Jinquan Liu ◽

Weizhong Chen ◽

Wen Nie ◽

Jingqiang Yuan ◽

Jingliang Dong

Keyword(s):

Mass Transfer ◽

Particle Size ◽

Experimental Research ◽

Water Inrush ◽

Size Distributions ◽

Particle Size Distributions ◽

Flow Properties ◽

Weathered Granite ◽

Completely Weathered Granite

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Diurnal and day-to-day characteristics of ambient particle mass size distributions from HR-ToF-AMS measurements at an urban site and a suburban site in Hong Kong

Atmospheric Chemistry and Physics ◽

10.5194/acp-17-13605-2017 ◽

2017 ◽

Vol 17 (22) ◽

pp. 13605-13624 ◽

Cited By ~ 3

Author(s):

Berto Paul Lee ◽

Hao Wang ◽

Chak Keung Chan

Keyword(s):

Particle Size ◽

Hong Kong ◽

Particle Mass ◽

Urban Site ◽

Size Distributions ◽

Particle Size Distributions ◽

Accumulation Mode ◽

Ambient Particle ◽

Mass Median ◽

Suburban Site

Abstract. Mass-concentration-based particle size distributions measured by a high-resolution aerosol mass spectrometer were systematically analyzed to assess long and short-term temporal characteristics of ambient particle size distributions sampled at a typical urban environment close to emission sources and a suburban coastal site representing a regional and local pollution receptor location in Hong Kong. Measured distributions were bimodal and deconvoluted into submodes, which were analyzed for day-to-day variations and diurnal variations. Traffic and cooking emissions at the urban site contributed substantially to particle mass in both modes, while notable decreases in mass median diameters were limited to the morning rush hour. Inorganic particle components displayed varying diurnal behavior, including nocturnal nitrate formation and daytime photochemical formation evident in both modes. Suburban particle size distributions exhibited notable seasonal disparities with differing influence of local formation, particularly in spring and summer, and transport which dominated in the fall season leading to notably higher sulfate and organic accumulation-mode particle concentrations. Variations in particle mixing state were evaluated by comparison of interspecies mass median diameter trends at both measurement sites. Internal mixing was prevalent in the accumulation mode in spring at the urban site, while greater frequency of time periods with external mixing of particle populations comprising different fractions of organic constituents was observed in summer. At the suburban site, sulfate and nitrate in the accumulation mode more frequently exhibited differing particle size distributions in all seasons, signifying a greater extent of external mixing. At the urban site, periods of greater submicron inorganic mass concentrations were more likely to be caused by increases in both Aitken- and accumulation-mode particle mass in summer, while at the suburban receptor location, organic and nitrate Aitken-mode particle mass contributed more regularly to higher total submicron species mass concentrations in most seasons (spring, summer, and winter).

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The description of solid wastes by particle mass instead of particle size distributions

Resources Conservation and Recycling ◽

10.1016/s0921-3449(01)00107-0 ◽

2002 ◽

Vol 34 (3) ◽

pp. 193-207 ◽

Cited By ~ 8

Author(s):

H von Blottnitz ◽

A Pehlken ◽

Th Pretz

Keyword(s):

Particle Size ◽

Solid Wastes ◽

Particle Mass ◽

Size Distributions ◽

Particle Size Distributions

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Diurnal and day-to-day characteristics of ambient particle mass size distributions from HR-ToF-AMS measurements at an urban site and a suburban site in Hong Kong

10.5194/acp-2017-162 ◽

2017 ◽

Author(s):

Berto P. Lee ◽

Hao Wang ◽

Chak K. Chan

Keyword(s):

Particle Size ◽

Hong Kong ◽

Particle Mass ◽

Urban Site ◽

Size Distributions ◽

Particle Size Distributions ◽

Accumulation Mode ◽

Ambient Particle ◽

Mass Median ◽

Suburban Site

Abstract. Mass concentration based particle size distributions measured by a high-resolution aerosol mass spectrometer were systematically analyzed to assess long and short-term temporal characteristics of ambient particle size distributions sampled at a typical urban environment close to emission sources and a suburban coastal site representing a regional and local pollution receptor location in Hong Kong. Measured distributions were bimodal and deconvoluted into submodes which were analyzed for day-to-day variations and diurnal variations. Traffic and cooking emissions at the urban site contributed substantially to particle mass in both modes, while notable decreases in mass median diameters were limited to the morning rush hour. Inorganic particle components displayed varying diurnal behavior, including nocturnal nitrate formation and daytime photochemical formation evident in both modes. Suburban particle size distributions exhibited notable seasonal disparities with differing influence of local formation, particularly in spring and summer, and transport which dominated in the fall season leading to notably higher sulfate and organic accumulation mode particle concentrations. Variations in particle mixing state were evaluated by comparison of inter-species mass median diameter trends at both measurement sites. Internal mixing was prevalent in the accumulation mode in spring at the urban site, while greater frequency of time periods with external mixing of particle populations comprising different fractions of organic constituents was observed in summer. At the suburban site, sulfate and nitrate in the accumulation mode more frequently exhibited differing particle size distributions in all seasons signifying a greater extent of external mixing. At the urban site, periods of greater submicron inorganic mass concentrations were more likely to be caused by increases in both Aitken and accumulation mode particle mass in summer, while at the suburban receptor location organic and nitrate Aitken mode particle mass contributed more regularly to higher total submicron species mass concentrations in most seasons (spring, summer and winter).

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