The relationship between climate conditions and airborne dust abundance in Zabol and Hirmand cities

Sistan plain has high erodibility because of fine grain alluvial deposits, drought and the continuous Levar northerly wind, commonly known as the ‘‘120-day wind’’ during dry seasons. This study aims to investigate relationship between climate characteristics and airborne dust abundances in two cities of Sistan plain from April to late September in 2015. Seven dust traps in Zabol and five dust traps in Hirmand were installed to measure airborne dust abundances monthly (according solar calendar). Monthly meteorological parameters including wind speed, air temperature, relative humidity and evaporation were used. The highest and lowest amounts of airborne dust deposits were observed in Hirmand city in August+September (4637.22 g/m2) and in Zabol city in April+May (92.88 g/m2), respectively. The positive correlation was observed between wind speed, evaporation and airborne dust abundances. The negative correlation was observed between air humidity, temperature and airborne dust deposits abundances. The meteorological station was located in the Zabol airport and it seems the relationship between airborne dust deposits and meteorological parameters was more reliable in Zabol than Hirmand. But total airborne dust abundance in Hirmand city was approximately 10 times more than Zabol and it could show the contribution of other effective factors on airborne dust deposit such as distances from dust source, frequency and duration of dust storms, vegetation cover, soil type and etc.