Applications of the lognormal frequency distribution to the chemical composition and size distribution of naturally occurring atmospheric aerosols

1971 ◽  
Vol 1 (1) ◽  
pp. 106-114 ◽  
Author(s):  
Irving H. Blifford ◽  
Dale A. Gillette
2017 ◽  
Author(s):  
Jiarong Li ◽  
Xinfeng Wang ◽  
Jianmin Chen ◽  
Chao Zhu ◽  
Weijun Li ◽  
...  

Abstract. Chemical composition of 39 cloud samples and droplet size distribution in 24 cloud events were investigated at the summit of Mt. Tai from July to October 2014. Inorganic ions, organic acids, metals, HCHO, H2O2, sulfur(IV), organic carbon, element carbon as well as pH and electrical conductivity were analyzed. The acidity of the cloud water significantly decreased from a reported value of pH 3.86 in 2007–2008 (Guo et al., 2012) to pH 5.87 in the present study. The concentrations of nitrate and ammonium were both increased since 2007–2008, but the overcompensation of ammonium led to the increase of the mean pH value. The microphysical properties showed that cloud droplets were smaller than 26.0 μm and the most were in the range of 6.0–9.0 μm. The maximum droplet number concentration (Nd) was associated with droplet sizes of 7.0 μm. Cloud droplets exhibited a strong interaction with atmospheric aerosols. High PM2.5 level resulted in higher concentrations of water soluble ions and smaller sizes with more numbers of cloud droplets, and further gave rise to relatively high acidity. High degrees of relative humidity facilitated the formation of large cloud droplets and led to high liquid water contents under low PM2.5 level. The cloud droplets to wet deposition acted as an important sink of soluble material in the atmosphere and the dilution effect of the water content should be considered when estimating concentrations of soluble components in the cloud phase.


Tellus ◽  
1982 ◽  
Vol 34 (2) ◽  
pp. 151-158 ◽  
Author(s):  
L. T. KHEMANI ◽  
G. A. MOMIN ◽  
M. S. NAIK ◽  
R. VIJAYAKUMAR ◽  
BH. V. RAMANA MURTY

1964 ◽  
Vol 101 (1) ◽  
pp. 76-93 ◽  
Author(s):  
K. A. Jones ◽  
A. K. Galwey

AbstractChemical and modal analyses have been made for a series of ten homogeneous specimens of meta-sediments, with identical metamorphic histories, from the aureôle of the Ardara pluton. Results showed that total amount of garnet was determined by the quanity of “free ferrous oxide” (assuming that the reaction: FeO + Fe2O3→ Fe3O4, has gone to completion) in the rock. Size distribution curves showed that each specimen contained crystals with a preferred radius and throughout the series a quantitative relation between the preferred radius and the frequency distribution about this value was observed.Measurement of the number of crystals per unit volume showed that this gave trends with functions of the chemical composition of the rock. A discussion of the mechanism of garnet formation in terms of chemical laws of nucleation and growth is given.


Tellus ◽  
1982 ◽  
Vol 34 (2) ◽  
pp. 151-158 ◽  
Author(s):  
L. T. Khemani ◽  
G. A. Momin ◽  
M. S. Naik ◽  
R. Vijayakumar ◽  
Bh. V. Ramana Murty

2011 ◽  
Vol 45 (6) ◽  
pp. 1251-1258 ◽  
Author(s):  
Jianjun Li ◽  
Gehui Wang ◽  
Bianhong Zhou ◽  
Chunlei Cheng ◽  
Junji Cao ◽  
...  

2014 ◽  
Vol 98 ◽  
pp. 271-282 ◽  
Author(s):  
Yolanda González-Castanedo ◽  
Teresa Moreno ◽  
Rocío Fernández-Camacho ◽  
Ana María Sánchez de la Campa ◽  
Andrés Alastuey ◽  
...  

2016 ◽  
Vol 16 (2) ◽  
pp. 777-797 ◽  
Author(s):  
A Vara-Vela ◽  
M. F. Andrade ◽  
P. Kumar ◽  
R. Y. Ynoue ◽  
A. G. Muñoz

Abstract. The objective of this work is to evaluate the impact of vehicular emissions on the formation of fine particles (PM2.5;  ≤  2.5 µm in diameter) in the Sao Paulo Metropolitan Area (SPMA) in Brazil, where ethanol is used intensively as a fuel in road vehicles. The Weather Research and Forecasting with Chemistry (WRF-Chem) model, which simulates feedbacks between meteorological variables and chemical species, is used as a photochemical modelling tool to describe the physico-chemical processes leading to the evolution of number and mass size distribution of particles through gas-to-particle conversion. A vehicular emission model based on statistical information of vehicular activity is applied to simulate vehicular emissions over the studied area. The simulation has been performed for a 1-month period (7 August–6 September 2012) to cover the availability of experimental data from the NUANCE-SPS (Narrowing the Uncertainties on Aerosol and Climate Changes in Sao Paulo State) project that aims to characterize emissions of atmospheric aerosols in the SPMA. The availability of experimental measurements of atmospheric aerosols and the application of the WRF-Chem model made it possible to represent some of the most important properties of fine particles in the SPMA such as the mass size distribution and chemical composition, besides allowing us to evaluate its formation potential through the gas-to-particle conversion processes. Results show that the emission of primary gases, mostly from vehicles, led to a production of secondary particles between 20 and 30 % in relation to the total mass concentration of PM2.5 in the downtown SPMA. Each of PM2.5 and primary natural aerosol (dust and sea salt) contributed with 40–50 % of the total PM10 (i.e. those  ≤  10 µm in diameter) concentration. Over 40 % of the formation of fine particles, by mass, was due to the emission of hydrocarbons, mainly aromatics. Furthermore, an increase in the number of small particles impaired the ultraviolet radiation and induced a decrease in ozone formation. The ground-level O3 concentration decreased by about 2 % when the aerosol-radiation feedback is taken into account.


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