Spatial and temporal Variability in the dust deposition rate of Yazd city and its relationship with some climatic parameters

Dust subsidence occurs widely in arid and semi-arid regions of the world. This study was conducted to investigate the temporal and spatial characteristics of atmospheric dust in Yazd. Dust was sampled seasonally from autumn 2018 to summer 2019 and from 30 points using sediment traps installed on the roofs of one-story buildings and the dust subsidence rate was determined. The results showed that the lowest dust subsidence rate in summer with an average of 13.27 g /m2 and the highest value with an average of 23.41 g/m2 was observed in spring and the average annual dust subsidence rate in the study area was found 72.7 tons/km2. Correlation charts showed that there is a negative and low correlation coefficient between the dust subsidence rate with minimum temperature (R2 = 0.28) and maximum temperature (R2 = 0.19). However, positive and strong correlation was observed with mean wind data (R2 = 0.941) and maximum wind speed (R2 = 0.905) and positive but low correlation with the number of dust observations (R2 = 0.09). Among the climatic parameters, wind speed in the study area seems to have had a greater impact on the occurrence of dust events as well as the rate of dust subsidence. According to the zoning maps, the prevailing winds, visiting different areas during the sampling, as well as the Google map of the area in the northern and northwestern and eastern areas of the region, there are deserts without vegetation and without buildings. In these areas, the subsidence rate has been higher and the lowest subsidence rate has been observed in the sampling stations of the city center with tall residential and office buildings in these areas. Interaction between different characteristics of dust sampling points such as altitude, proximity to high-traffic and high-traffic areas, proximity to areas of civil activities, distance from dust production areas, prevailing wind direction and amount and distribution of wind speed and wind speed on the rate dust subsidence has affected different parts of the study area, leading to an uneven distribution of dust subsidence rates in the area.