Spatial Variability of Atmosphere Dust Fallout Flux in Urban-Industrial Environments

This work aimed to study the spatial variability of particulate matter deposition flux in urban-industrial environments. The main objective was to identify areas with higher deposition flux and associate the variability with climatological variables and with possible surrounding emitting sources. The method for collecting the deposited particles was based on the standard NF X 43-007. Sampling for particulate matter took place between April 2015 and February 2016, through seven sampling campaigns. Maps of the spatial dispersion for the particulate matter were obtained through statistics and geostatistics techniques. Elemental identification by scanning electron microscopy (SEM) was also used in two sampling campaigns. The results show that the sampling campaigns that took place during hot and dry periods, 2nd and 3rd, present higher deposition flux: 2.04 g/(m2 x month) and 1.72 g/(m2 x month), respectively. Lower deposition fluxes were registered in the 6th and 7th campaigns: 0.23 g/(m2 x month) and 0.24 g/(m2 x month), respectively. It was also observed a recurrent high deposition at specific sampling points which may be due to both the nearby road traffic and the presence of chimneys. SEM analysis allowed to associate repetitive element deposition, at the same sampling point, to the same emitting source.