مطالعه ویژگی‌ های فیزیکی - شیمیایی و غلظت هواویزی ‌های جوی با دستگاه شمارنده آبشاری ذرات (مورد مطالعه توفان گرد و غبار منطقه یزد)

هدف این پژوهش شناسایی برخی از مولفه‌های فیزیکی و شیمیایی ذرات معلق در هنگام توفان با استفاده از نمونه‌گیری و روش‌های آزمایشگاهی و همچنین آشکارسازی منبع و مسیر توفان‌ها با استفاده از مدل پخشی hysplit در شهر یزد است. با استفاده از نمونه‌برداری از ذرات معلق در هنگام توفان با دستگاه جمع‌کننده ذرات به‌روش آبشاری، مقادیر ذرات گردوغبار اندازه‌گیری شد و غلظت ذرات pm10 و pm2.5 حاصل با مقادیر گزارش شده از سازمان‌های محیط‌زیست و هواشناسی استان یزد مورد مقایسه قرار گرفت. در ادامه با استفاده از مدل hysplit در پنج ارتفاع منبع و مسیر توفان مورد بررسی قرار گرفت که در توفان مربوط به روز سه اردیبهشت مسیرها جهت جنوب غربی منطقه هدف که بخشی از شهرستان‌های تفت و مهریز را شامل می‌شود، نشان دادند. سپس با استفاده از دستگاه طیف‌سنج جذب اتمی، مقادیر فلزات سنگین pb, al, cd موجود در نمونه‌های مربوط به توفان‌های 29 مرداد و 29 شهریور مورد بررسی قرار گرفت. در آزمایش‌ مربوط به تاریخ 29 مرداد، عنصر سرب در محدوده غنی‌شدگی کم (ef<3)، که ef نشان‌دهنده مقدار افزایش غلظت یک عنصر نسبت به غلظت طبیعی آن در پوسته، سنگ بستر یا خاک است، و عنصر کادمیوم در اکثر فیلترها، در محدوده غنی‌شدگی شدید (10

study of physicsl-chemical characteristics and concentration of aerosols derived from cascade impactor (case of dust storm in yazd area)

due to the lack of laboratory studies in the field of detection of aerosols and dust in iran and in yazd, in this study, using laboratory methods such as cascade impactor, a vacuum pump for sampling aerosols, rotameter and other laboratory materials in the field samples have been analyzed for characteristics of dust particles such as pm10 and pm2.5 particles, and then the particle concentration has been obtained by weighing the specimens. qualitative and quantitative studies of aerosols existing inside the dust storms is an effective procedure to identify their environmental effects and source detection. increasing the frequency of these phenomena in desert areas with hot and dry climates, such as yazd province, is another aspect of climate change, in that dry climates that are getting drier. on the other hand, increasing temperature due to global warming result in the extension of deserts. the main purpose of this study is identification and comparison of some the physical and chemical characteristics of aerosols existing inside dust storms with model results. for this purpose, we used 7-stage cascade impactor, with specific sampling rate and laboratory methods, aligned with pm2.5 and pm10 data.in this study, four days of storms (3 and 23 may, 29 august and 29 september 2018) were examined. at first, with the use of 7-stage cascade impactor, aerosols of dust storm in the range of 0.4-10 µm are collected in different stages and their values were compared with pm10 and pm2.5 concentrations of particles with the reported values of environmental and meteorological organizations of yazd city. cascade impactor works with a specific pump in that the sampling inflow of air is 28.4 l/min in that the inflow was adjusted with a mechanical rotameter. the weight of filters was measured before and after the sampling. these filters were placed in the desiccator in order to eliminate the humidity from them. the results showed the compatibility of 24-hour accumulation of hourly data with cascade impactor results. then, with using atomic absorption spectrometry device, the values of heavy metals such as pb, al, cd in the samples related to the storms of 29 august and 29 september were examined. in the august 29 test, the lead element was in the low enrichment range (ef <3), and the cadmium element in most filters was in the high enrichment range (10