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Aerosols are solid or liquid particles suspended in the earth's atmosphere, which enter the earth's atmosphere from both natural and human sources. The wind blowing in the deserts, the evaporation of oceans and seas, the eruption of volcanoes, and the burning of forests and pastures are natural sources, and the burning of fossil fuels and the change of the earth's surface cover are human sources of their production. Aerosols can be classified into four types: dusty, marine, urbanindustrial, and biomass burning particles. Due to the significant temporal and spatial changes of aerosols and for properly understand their climatic effects, we need to use long-term measurements of satellites and ground-based instruments. Measurements made from space and ground have allowed us to have a detailed view of the properties and effects of different types of atmospheric particles. Ground-based remote sensing is one of the powerful methods for determining the optical and physical properties of atmospheric aerosols. The sun-photometer (SPM) is a spectrometer that records the intensity of the sun's radiation usually in four wavelength channels of 440, 675, 870, and 1020 nm in two modes of measuring the sun and the sky with a limited viewing angle of 1.2 degrees during the day. Spectral aerosol optical depth, columnar water vapor, Angstrom exponent, single scattering albedo, polarized phase function, the real and imaginary refractive index of aerosols, and degree of linear polarization of sunlight are characteristics of atmospheric particles that are extracted from SPM measurements. There are different methods for classifying aerosols using data extracted from SPM measurements. One of the most common methods is to use aerosol optical depth data (a measure of the amount of atmospheric suspended particles) in terms of the Angstrom exponent (a qualitative measure of the dimensions of atmospheric particles). By combining other parameters obtained from the mode of the sun and the sky of the SPM, such as the aerosol optical depth, Angstrom exponent, particle size distribution, and refractive index, atmospheric aerosols can be classified. Our aim in this article is to investigate the ability of the degree of linear polarization parameter to classify the atmospheric particles. The degree of linear polarization measures the linear polarization of sunlight scattered by atmospheric particles (molecules and aerosols). For this purpose, the data of four sites of Banizoumbou, Beijing, El-Arenosillo, and Minsk, which have dusty, urban-industrial, marine, and biomass-dominant particles, respectively, were selected from the AERONET (AErosol RObotic NETwork) data. This paper uses three parameters of aerosol optical depth, Angstrom exponent, and degree of linear polarization extracted from SPM data. The results show that the maximum value of the degree of linear polarization (standard deviation) at the wavelength of 870 nm for dusty (Banizoumbou), urban-industrial (Beijing), marine (El-Arenosillo) and biomass (Minsk) aerosols are equal to 0.14 (0.05), 0.35 (0.10), 0.47 (0.08) and 0.37 (0.08) respectively. Therefore, the parameter of the degree of linear polarization is able to separate dusty, urban-industrial, and marine atmospheric particles from each other. However, biomass particles overlap a lot with urban-industrial aerosols and cannot be separated from each other. [ABSTRACT FROM AUTHOR]

The use of polymers to control wind erosion has been considered in recent years. However, before recommending them as mulch, their effects on the environment and reduction of wind erosion should be investigated. In this paper, the effect of Imen Asia polymer in stabilizing quicksands and reducing wind erosion in both laboratory and field sections in the Lower Jargooiyeh region was investigated. For this purpose, first, an emulsion of polymer in water with a ratio of one to three (one-part polymer in two parts water) was prepared and to investigate its effect on reducing erosion, a volume of emulsion containing 80, 100, and 120 kg of polymer in 25 m2 plots Sprayed with three repetitions. The results showed that the wind erosion threshold speed after mulching increased from 3.5 to more than 11 m / s in all treatments. The study of the environmental effects of the polymer showed that the concentration of mulch did not affect the germination of native plants and the lifestyle of insects and rodents in the area. The effect of polymer on the physical and chemical properties of soil, including changes in the number of toxic elements and heavy metals on the soil before and after mulching, also confirms that it does not have a negative effect on these properties. Economically, the cost of using this polymer per hectare was evaluated. Based on the net present value (NVP) of this material and its internal rate of return (IRR), the economics of using it and investing in the use of this polymer as mulch are justified. Due to the lack of harmful effects on the environment and the ability to reduce wind erosion and economical to oil mulch, the use of this polymer as mulch is recommended. [ABSTRACT FROM AUTHOR]

In this research, dust storms in the west of Iran have been investigated, which include days when the dust suspension brings the horizontal visibility to less than or equal to one kilometer in at least three meteorological stations. In order to extract synoptic patterns, the data were obtained on sea level pressure, geopotential height, temperature, zonal (u) and meridional (v) components of wind at different levels of the atmosphere related to ERA-Interim. Using the visual analysis of the maps, the maps were categorized based on the similarity between the pressure patterns. The analysis of synoptic patterns showed that the dynamic and thermal cyclone patterns are the most important patterns of the dust cycle in Iran. In the storms caused by a dynamic cyclone, according to the location of the cyclone in the region, the most dust rise was found to be from the western and southwestern cyclone in Iraq, so about 40% of these storms came from the central lakes and especially from Lake Tharthar. The storms caused by thermal cyclones in the region have lower intensity than those caused by dynamic cyclones. The sources located in the southern half of Iraq, northern Arabia, Kuwait and southwestern Iran have been more effective in the occurrence of dust than the other parts in the region. [ABSTRACT FROM AUTHOR]

In this paper, using reanalysis ERA5 data and observational data, the effect of Low-Level Jet (LLJ) on dust in the west and south-west of Iran during the period 2007-2017 is studied. The vertical wind shear transfers the momentum from the jet level to the surface and then transfers dust from the sources, so to identify the LLJ besides the maximum wind speed, the vertical wind shear is also considered. Moreover, the horizontal and vertical range of LLJ, average of long term frequency of LLJ and monthly and seasonal frequency of dust are calculated in this study. The result of the comparison of observational data with ERA5 data shows that 10 m wind speed of ERA5 is larger than of observational data. Strong north to south pressure gradient due to the high pressure system over Iraq and Zagros and the low pressure system over the south-west of Iran, is the most important synoptic forcing that causes strong north and north-westerly and LLJ winds over the study area. Furthermore, region topography, land-sea breeze, weak surface tension over the Persian Gulf, temperature differences and special heat capacities between land and sea are other factors that form and affect the intensity of LLJ. The monthly wind speed distribution shows the maximum average wind speed 10 m/s in July and its minimum 2 m/s in January. The average height of the boundary layer varies from 2400 meters by days to 150 meters at nights, which is one of the main causes of LLJ. The highest frequency of dust in Ahvaz was in July 2009 with 30 days of dust. [ABSTRACT FROM AUTHOR]

This research investigated the specific patterns of dust influx into the metropolis of Tehran from 2005 to 2017. The study utilized the data on dust occurrence days and synoptic station data in Tehran. The research methodology involved employing the HYSPLIT trajectory model, as well as dust detection indices, and determining the chemical properties of dust, including main and rare elements, by using the X-Ray Fluorescence (XRF) method. The findings indicated that the primary source of dust entering Tehran originated from desert regions and vast, arid areas outside the country. External sources of dust, such as the North Arabian Sahara and the East African Sahara, have been active since ancient times and are not solely related to modern dust occurrences. The cause of their impact on Tehran could be attributed to the desiccation of internal lagoons and lakes. The changes in the frequency of fine-dust trajectories could not be solely explained by their connection with external sources. Instead, it appeared that the micro-particle movement system was striving to establish a deeper order, which was not solely influenced by changes in the origin and destination of the particles. Rather, the entry of fine particles into this movement system had undergone changes during their movement within the system. [ABSTRACT FROM AUTHOR]

Climatic phenomena in different regions of the world are different in relation to the geographical characteristics of each region. Dust is one of the dominant atmospheric phenomena in desert and semi-desert regions of the world. This phenomenon is related to air pollution in most parts of Iran with dry climate, including Birjand in eastern Iran. The origin and direction of dust in this area are varied in the year, and knowing them helps urban risk management, forecasting and desertification. In this study, Landsat satellite images were used to determine the origin of dust in the period of 1955-2017. The dust day was defined based on the classification of Shao and Dong with code 06 and 07 with horizontal visibility of less than 10 km, and revealed with BTD and TDI index. To determine dust atmospheric patterns, grid data from NOAA was used, and dust trajectories were carried out with the HYSPLIT model. The results showed that the most dust days in 1963 and 2008 (45 years), with 148 and 128 days, respectively, which mainly occur in the warm season and July. The 120-day winds of Sistan in the east of Iran plays a major role in transporting dust particles and air pollution in Birjand from the east and northeast from the deserts of Central Asia, Turkmenistan, Afghanistan, Khorasan Razavi plains and interior plains. But in the cold period of the year, Siberian cold masses from the east, cold fronts (migrating anticyclone), occluded fronts and low pressures from the northwest, west and southwest by passing through the central plains of Iran and sometimes the deserts of Syria and Iraq causes dust in the upper levels of the atmosphere. In all these centers, the occurrence of particles and pollution of cities prevails during periods of drought. [ABSTRACT FROM AUTHOR]

Background and Objectives: Dust storm is a phenomenon that occurs in arid and semi-arid regions due to high wind speed and turbulence on the surface of the soil without cover and prone to erosion. Dust changes the radiant budget of the earth's surface and changes the temperature of the earth's surface and atmosphere. Therefore, dust affects the energy exchange between the surface and the atmosphere as well as the dynamics of the atmosphere. Recognizing and studying the trend of dust storms and their relationship with climate change is one of the most important ways to reduce the damage caused by this phenomenon. This study amies to evaluate the effect of dust storms on radiation indices and heat flux according to the combination of satellite remote sensing information and re-analysis data in Hirmand basin. Materials and Methods: In this research ERA5 re-analysis and Terra satellite data used for the August 23-26, 2010 event in Hirmand. Products and satellite data used to include true color images and AOD and re-analysis data including Surface latent heat flux (SLHF), Surface Sensible Heat Flux (SSHF), Surface net Solar Radiation (SSR), Surface net Thermal Radiation (STR) and Balance Radiation (Rn). Dust particles were routed using the HYSPLIT model and wind speed in the study area was also assessed using the analysis data. Also, for validation of satellite data and re-analysis, visibility and air temperature data, at height of 2 meters, at Zabol Meteorological Station, closest station to the study area, were analyzed. Results: According to the HYSPLIT model output, most of the dust particles were collected from the deserts of Turkmenistan and then the dry areas around Lake Hamun and parts of northern Pakistan. AOD values showed that from August 21, the value of this index gradually increased so that on the 25th day, the maximum AOD value reached 1.25. Examination of the values of radiation and heat flux indices showed a significant decrease in SSHF, SSR, STR and Rn indices and their values reached the lowest value on the 26th day and the SLHF index with a slight difference on the 25th day reached its lowest value of 58 w/m2. Correlation study showed that SSR and Rn indices with -0.370 and -0.359 respectively had the highest and SLHF index with -0.153 showed the lowest correlation with AOD index. Conclusion: The results of this study showed that the western parts of Hirmand Basin, Lavar or North wind has emitted dust particles into atmosphere, and the region and rotational currents has caused the distribution of these particles in the study area. The results of satellite data and their re-analysis and matching with real images showed that the study event increased the optical depth of dust particles, which resulted in tangible and surface heat fluxes, solar and thermal radiation, as well as balance. Radiation was greatly reduced. Evaluation of horizontal visibility and air temperature data at a height of 2 meters at Zabol station also confirmed the results of satellite images and re-analysis data. [ABSTRACT FROM AUTHOR]

Statement of the Problem: The most important center of dust production in Isfahan province is the Segzi-Rudasht center. This center with an area of 801520 hectares is located in the east of the historical city of Isfahan. The study area, despite its great economic potential, is in a state of imbalance due to drought, reduced agricultural activities, lack of employment facilities leading to unemployment and lack of the demand for labor. This imbalance could become more critical in the coming years due to declining water resources and increasing particulate matter. Several factors, with different degrees of influence, have been involved in creating and spreading dust in the east of Isfahan. Aim: The aim of the present study is to determine the role of different factors in the creation and spread of dust in the east of Isfahan province. Methods: This research is a survey research using questionnaires designed appropriate to the statistical population of the study to achieve the research objectives. Semi-structured interviews and observations were also used. The validity of the questionnaires was evaluated by a panel of experts and using their opinions in the field of natural resources and desertification. The reliability of the questionnaires was assessed through a pilot study by calculating the Cronbach's alpha coefficient. To analyze the data, various methods of descriptive and inferential statistics such as PCA factor analysis, stakeholder network analysis using SPSS/PC, and TOPSIS software were used. Results: The results of the present study show the importance of water and agriculture factors in intensifying desertification in the Segzi-Rudasht pilot. After the water and agriculture factors are economic factors, management factors, policies and laws, social factors, and finally developmental and technological factors, respectively. Innovation: The use of scientific methods and techniques to determine the importance of factors in the absence of desertification is an innovation of the present study because the effect of desertification factors at this level has not been studied so far. [ABSTRACT FROM AUTHOR]

In recent decades, dust storms have intensified due to climate changes, including drought and human interventions. In addition to removing soil particles, dust brings storms bring about severe economic, social, and health problems. Due to its strategic conditions – including its status as an industrial and agricultural hub and the province hosting more than 29 million Iranian and international pilgrims, especially during the seasons and months with specific holidays – should be prioritized in the examination of dust storm frequency. The purpose of this study was to examine and track the frequency of dust storms and analyze the effect of climactic changes on them through the investigation of drought trend as well as the trend of changes in the land surface coverage percentage during the statistical analysis period. The results of counting the dust codes showed that dust storms with local origin had the highest frequency. According to the monthly analysis, Sarakhs and Mashhad stations had the most dust phenomena, with the most dusty days in the study area during summer and spring seasons, especially June and July months. The results of regression analysis of drought index and the monthly local dusty days indicated the existence of a significant, positive relationship between dust increase and drought intensity in Mashhad and Sarakhs stations during the statistical period of 27 years at 99 percent confidence interval. Finally, in the light of the results obtained from the examination of the land surface changes, it is recommended that land use plans be used along with short-term methods of soil stabilization in order to reduce the economic damages and preserve people’s health against dust during busy months and seasons so as to achieve the goals of long-term methods. [ABSTRACT FROM AUTHOR]

Isfahan province is beset by vegetation poverty in most of its pastures due to such climatic characteristics as low rainfall, high variability, high temperature, and high evapotranspiration especially in desert areas. The occurrence of erosions by the least wind blow in some areas has caused a flow of sand to cities, villages, military centers and so on. Therefore, recognizing wind tunnel removal sites can be of considerable help in combating wind erosion. In this paper, using meteorological and meteorological data, we tried to study the general morphology of sand dunes and the wind regime in each region in Segesi plain located in Isfahan province. Also, by locating harvest areas and identifying erosion-sensitive faces, we identified the areas that play the most role in wind sediments. The areas that are under wind erosion and without vegetation are identified to be the main source of dust. The distribution of available drug species and the NDVI vegetation in the region were studied too. The corresponding areas are good places where to plant medicinal plants, especially the herb Alhagi persarum, to reduce dust. Considering that this herb has the widest dispersal in the area, combining this map with the map of critical erosion centers indicates that the areas poorly covered by vegetation undego the worst wind erosion.

Dust phenomenon with the effect on different parts of society, is one of the important challenges in the world. So, accurate assessment of the effects of dust and consequently codification of regional and global policies are necessary for reducing the negative effects of this phenomenon. Therefore, in this study, the willingness to pay of Ahvaz County people for improving air quality in the face of the dust phenomenon was estimated using contingent valuation method and logit model. Data were gathered by 144 questionnaires using dual two-dimensional method of people in Ahvaz County in 2016. In this study, willingness to pay was estimated for improving air quality in Ahvaz at two levels of typical decrease in pollution (appropriate for doing everyday tasks) and decrease to international standards which was a study performing for the first time in Iran. In current study, in both levels, the variables of income and age positively impacted on the probability of accepting the offered price and while the variable of suggestion negatively impacted on the probability of accepting the offered prices. In addition to the two mentioned variables, the number of household members showed a significant and negative for reducing pollution to typical levels. In case of international standards, membership in organizations related to natural resources and agriculture department and gender variables had negative influence while education showed a significant and positive impact. In this study, the proposed value to pay in the first and second levels (suggested levels) were 10619 and 24851 Rials, respectively. [ABSTRACT FROM AUTHOR]

1-Introduction One of the natural hazards resulted in great damages in dry and wild regions of world and Iran annually is the occurrence of dusty and black storms. Due to Iran geographical situation in arid and semiarid zone of the world, this country is continually exposed to local and synoptic dust systems. Yazd province is also exposed to various dust systems and this destructive phenomenon because of climatic and geographical conditions and adjacency to deserts in neighbor countries. Therefore, the knowledge of this phenomenon can be an efficient step towards its destructive effects, in particular in stabilizing smooth sands within this region. 2-Data and Methods In this research, using wind direction and speed data, horizontal view, pressure, temperature, humidity, could and dust phenomenon in synoptic stations, synoptic maps in the ground surface, 850 and 500 hpa levels, omega, wind vector, wind stream, humid blowing and cyclone and atmospheric data above Yazd station, dusty and black storms in low atmospheric levels were studied during 17 stages in selecting the sample in 1989-2009 years. The necessary maps were taken since two days before starting dust until its peak from NCEP/NCAR databases and drawn in GrADS software. 3-Result and Discussion The results of the research show three dust storm patterns and strong winds during three autumn, winter and spring seasons. The first is autumn pattern (storm October 2, 1997) in which there are pressure gradient between south and central areas of Iran and a hod with deep amplitude in 850 and 500 hecto-pascal levels in western Iran and Yzad province which it couldn’t be fed well in terms of temperature and humidity. The passage of hod and releasing its energy and long term dryness in summer across this region resulted in blowing strong winds and dust storm in this province, especially in Yazd-Ardekan plain. The second is winter pattern (storm February 22, 2009) due to the presence of low-pressure center over the ground and along with deep hods in high levels as well as the passage of cold front through the province and the contact between cold air mass behind front and warm air mass dominant over region. After passing the cold front, sudden downfall of cold air can increase wind speed greatly in dry atmosphere and reduce horizontal view and the occurrence of dust storm in this region. The third is spring pattern (storm may 29, 2003) in which deployment of low pressure cell on the surface of the ground, tilting hod hinge in the upper levels of atmosphere across western Iran and its quick movement and sending short waves through central Iran and Yazd province along with the passage of cold dry and weak front from western north resulted in upward strong flows, high air instability and very serious dust and black storms in Yazd province and get to zero the horizontal view. 4-Conclusion The results of the research show three dust storm patterns and strong winds during three autumn (storm October 2, 1997), winter (storm February 22, 2009) and spring (storm may 29, 2003) seasons. The majority of such storms occur in afternoon hours and in may month and its strong winds mostly blow from west to western north. [ABSTRACT FROM AUTHOR]

Background: The date palm cultivation has a long history in Bushehr province. Throughout the recent decade; the dusts, in addition to direct harmful effects on humans, have adverse effects on health of the population living in this area. The infestation of pests in the southern province of Bushehr has groves. Due to the importance of dates in this area, the total ash and acid insoluble ash as indexes for assessing of chemical pollution and also, mold and yeast as indicators for microbial contamination were evaluated. Recently in a number of dates packaging industries, washing the products after the harvest is done. In current study, the effects of rinsing to decrease the dust pollution on date palm along with, the time effect on the quality and durability of washed and un-washed dates were investigated. Materials and Methods: Overall, 48 washed and un-washed dates were sampled from traditional and technologically advanced packaging industries, equally, and were confirmed according to ISIRI methods. Results: The Averages of total and acid insoluble ashes in washed date samples were:1.05±0.14 and 3.32±0.32%, and for un-washed samples were 1.36±0.27 and 4.59±1.64 percent, respectively. In all date samples were presented the yeast, however, their means were lower than the maximum limit (1 x 104 CFU). Also, all date samples were moldy. The Mean percentage of total ash samples in un-rinsed and rinsed dates were approximately, 1.84 and 1.33 times more than the maximum permissible limit, respectively. The mean of acid insoluble ash in all samples (100%), and 98% of total ash were higher than acceptable levels (p<0.05). The results revealed that the average percentage difference between the two groups were transpicuous, while this difference was not significant (p=0.13). Under the similar conditions, the average amount of yeast in washed date samples, were significantly different (p<0.05) and more than un-wash samples. The Mold levels in un-rinsed and rinsed samples; were 83.3 and 75% higher than the maximum permissible limit. According to the results, regardless of a decrease in amount of molds in washed samples than un-wash samples, the rinsing, was unable to eliminate the pollution, or even decreased it to acceptable levels. Conclusion: According to the findings, present rinsing is not an appropriate method for long storage. Observations, after one year upkeep in the same conditions, expressed that all un-washed date samples were apparently healthy, without any pests and insects. While 91.6% of the washed samples were insectivores, also their textured appearances were very unpleasant. [ABSTRACT FROM AUTHOR]