AIT QUALITY IMPACT ASSESSMENT OF FLUORIDE EMISSIONS FROM AN ALUMINUM SMELTER. THE ROLE OF PARTICLE RESUSPENSION ON THE DISPERSAL PATTERNS.

ALLENDE, DAVID; PULIAFITO, ENRIQUE; RUGGERI MARÍA F.; PASCUAL, ROMINA M.; MULENA, GABRIELA CELESTE; CREMADES, PABLO

Environmental Science and Engineering Volume 3 : Air and Noise Pollution

STUDIUM PRESS

Lugar: Darya Ganj New Delhi; Año: 2017; p. 110 - 129

Fluoride, released to the environment by several industrial processes, like aluminium smelters and ceramic factories, constitute one of the most important phytotoxic air pollutants. Fluoride concentration in the air depends not only on the industrial emissions but also on meteorological factors and topography. The purpose of this study was to estimate the impact of atmospheric emissions generated by a typical aluminum smelter on the surrounding area, in order to answer the following questions: (1) what is the dispersal pattern of environmental contamination by airborne fluoride produced by the industrial activity, (2) maximum distance of atmospheric contaminant dispersion and deposition patterns (3) the relevance of particulate fluoride suspension for air quality. The study was performed in the vicinity of the city of Puerto Madryn, Argentina (42.7°S, 34 65.05°W, 40 m a.m.s.l.) in the east of the Patagonia in a flat region with low difference in levels and maximum altitudes of 140 m. The present work examined the fluoride atmospheric dispersion from a large aluminum smelter located NW of the urban center. With that purpose we used the CALPUFF dispersion model in a 38 15 km × 15 km modelling domain around the aluminum plant. Surface meteorological observations for 426 days were obtained from three local surface stations and upper air required meteorological parameters were derived from the Weather Research and Forecasting (WRF) model. The CALWRF off-line preprocessor was used to generate an intermediate three dimensional data 56 file to be used by CALMET as a "first-guess" meteorological field. The WRF model was run with nested domains, reaching a resolution of 3 km, high enough to resolve the important meteorological features which can only be simulated by the prognostic WRF model, such as land and sea breezes. Gaseous hydrogen fluoride and particulate fluorides emissions from the aluminum reduction processes were directly measured at the stacks. Monitoring data from three different measuring campaigns were used to validate the model outputs. Potential sources of fugitive particulate emissions were estimated using particle deposition fluxes to calculate possible realizing areas. The area around the aluminium smelter doesn´t presents signs of fluoride contamination, as can be proved by the mean values obtained for both simulation and measurement, that are below air quality standards, except for a short period in wintertime. Particulate fluoride measurements far away from the aluminum plant can only be explained though particle resuspension, that can contribute up to 50% of the total measured concentrations.