Dust Particle Size and Statistical Parameters

Grain ‘size’ can be specified and measured in several different ways. All methods of grain size determination have blemishes, and the choice of the most appropriate method is governed by the nature of the sample and the use to which the data are placed. Four main methods are currently used for size analysis of sands: (a) sieving; (b) settling tube analysis; (c) electro-optical methods, including Coulter Counter analysis and laser granulometry; and (d) computerized image analysis. The classification of the particle size distribution of Kuwait dust was mapped according to the parameters proposed by Folk And Ward (1957) which were widely used for quantitative comparisons between natural grain size distribution and the lognormal distribution that shows better sorted sediments have lower values of σ1. Maps of the distribution of dust in Kuwait were obtained that included: fine sand (F.S.), Coarse sand (C.S), Medium Sand (M.S), Very Fine Sane (V.F.S), Very Coarse Silt (V.C.Silt), Coarse Silt (C.Silt), Medium Silt (M.Silt), Fine Silt (F.Silt), Very Fine Silt (V.F.Silt), in addition to that, the deposition percentage of Clay, Sand, mud (silt plus clay) and silt were provided.

Mineralogy (XRD)

The two main particle size components of the dust samples were subjected to mineralogical analysis to identify the mineral constituents and determine their frequency percentage in each textural class; the fine sand (particle size between 0.125 and 0.063 mm) and Mud (less than 0.063 mm). The average percentage of minerals was mapped out for each season i.e. March, June, September and December 2010 showing the high and low mineral concentration in areas in Kuwait covering the mineral concentrations of Calcite, Carbonate, clay minerals, dolomite, feldspars, and quartz.

Other Properties (BET Surface Area, Conductivity, Organic Matter, and pH)

Brunauer, Emmett, and Teller (BET) test were applied to dust samples in which samples (BET) surface area is highly related to the roundness of dust particles. The higher angularity and low roundness of the dust particles show a higher (BET) surface area. The roundness is also related to the particlesize distribution and mineralogical composition. The electrical conductivity test relates very well with the chemical and physical properties of dust samples in the transmission of an electrical current. The organic matter content was measured using the ignition method and the pH of the samples was recorded. Maps of the distribution of high and low BET concentrations, electrical conductivity EC, organic matter content, pH.

Deposited Rates of Radionuclides

Temporal and Spatial Distribution of Radionuclides in Dust Fallout. The depositional fluxes of the natural radionuclides (40K, 210Pb, and 7Be) and the man-made radionuclides (137Cs) have been calculated using efficiency calibrated ultra-low background gamma spectrometry in nine sampling sites covering Kuwait. Maps showing high and low concentrations of radionuclides distribution among Kuwait.

Deposited Dust

A dust storm is meteorologically defined whenever visibility is less than 1,000 meters (Al-Kulaib 1990). Al-Dousari (2009) lists Kuwait as having one of the highest dust precipitation rates in the world. Safar (1980) states that the annual average number of dusty days due to dust storms or rising dust or suspended dust in Kuwait is 255.4. Forty-seven sampling sites representing all the geomorphological and sedimentological provinces in Kuwait were selected for the installation of dust traps to measure the average annual amount of deposited dust during 2009–2010 and 2010–2011 in tons.km-2.

Spectro Absorption

Ultraviolet–visible UV-VIS. Varian Bio Cary 100 UV–VIS instrument was used for measuring the spectrum of dust samples. The certified materials according to Lab sphere SRS. 99–020 were used and the dust samples were placed in a cuvette (10 mm) and placed on the diffuse reflectance accessory. Measurement was done with respect to the reference. The UV–VIS spectra cover the regions from 900 to 190 nm which includes the near-infrared region, visible light regions, and ultraviolet regions. The FT-IR data shows the different chemical content of dust in the scanning of what possible compounds can be found in dust particles for required further analysis. The dust absorption of the light spectrum in Kuwait was revealed in maps according to seasons showing higher and lower concentrations of light absorption of ultraviolet, violet, blue, cyan, green, yellow, orange, red, infrared.

Inductively Coupled Plasma (ICP)

The crushed powder from defined dust particlesize fractions was analyzed using inductively coupled spectrometry plasma (ICP) for major and trace elements. The ICP was used for the determination of concentrations of trace elements and six major elements: (Al, Fe, Mg, Ca, Na, and K) and five minor elements (Ba, Cr, V, Ti, and Pb). They are quoted in part per million (ppm). Maps showing high and low concentrations of ICPamong Kuwait.

Dust Storm Satellite Images

DATA of Aerosol Robotic Network (Aeronet) stations and Ozone Monitoring Instrument (OMI) were obtained to get valuable and reliable information about the occurrence of dust events. In addition to Total Ozone Mapping Spectrometer (TOMS) provide informative and long dust events record. To analyze the dust time series, monthly, annual and seasonal linear trends are applied to the dust time series. This is achieved by summing the total number of dusty hours for each month and then the total number of dusty days for the month is calculated. Dust trend analysis includes; annual, winter, spring, summer and autumn with the rate of change. Dust frequency of seasons in days/season before and after sorting in a descending manner from 1984 to 2013. Satelliteimagesuse for PM2.5 Estimation and concentrations Remote sensing-based measurements Calibration of Field and Laboratory Equipment. Particle concentrations in different size ranges and the total suspended particulate matter in the air in Kuwait. Dust deposition rates were monitored and analyzed in Kuwait at the northern ArabianGulf to estimate quantities of fallen dust within major eight dust trajectories in the ArabianGulf. Kuwait is surrounded by five major sources of dust rather than intermediate dust source areas that are listed. Satelliteimages from 2000 to 2010 were used to identify major dust trajectories within seven major deserts in the world.

Pollen in Dust

Twenty-eight pairs of pollen and aeolian dust traps covering the State of Kuwait were used to obtain seasonal pollen counts of the most eight dominant families during 2009–2011 i.e. Chenopodiaceae, Poaceae (Gramineae), Cyperaceae, Leguminosae (Fabaceae), Cyperaceae, Brassicaceae, Malvaceae, Compositae, and Plantaginaceae. The sampling site locations were chosen to cover all the geomorphological sectors and native vegetation areas in Kuwait. Generally, pollen counts show us a remarkable distinction between the year 2009–2010 and 2010–2011, It is also evident that pollen counts (concentration) vary from season to season. Pollen counts over four seasons for two years (October 2009–August 2011) reveal the presence of two peaks in spring (April–May) and autumn (October–November). Map distribution of pollens in each of the dominant plant families in Kuwait is generated according to seasons showing higher and lower concentrations of dust pollen counts.