Caracterização de espécies inorgânicas solúveis no Material Particulado Total (MPT) atmosférico de Manaus

Abstract

The city of Manaus has been growth in recent decades mainly due to the secondary sector because of industries, as well as the tourism, leading increasing construction and the vehicle fleet. Consequently, there were an increase of pollutant generation, especially the emission of the total particulate matter (TPM) to the atmosphere. The TPM in the atmosphere is mainly related to resuspension of soil, industrial and vehicular emissions, or to reactions in the atmosphere with gases released by burning fossil fuels, such as NOx and SOx. The purpose of this study is to quantify the soluble inorganic species, especially the ions Cl-, NO3 -, SO4 2-, PO4 3- NO2 -, F-, Br-, K+, Ca2+, Mg2+, Li+ and NH4 +, in the total particulate matter collected in four locations of Manaus city, with different characteristics: industrial, vehicular, green urban area and the background, a location with a minimum human interference. The active sampling was performed with average flow of 19,5 ± 2,5 L min-1 weekly for 8 hours. Samples were collected in the rainy season (between December 2012 and March 2013) and in the dry season (June- August 2013), The ions were determined by ion chromatography with conductometric detection. Among all ions studied, those that stood out were NO3 -, SO4 2-, K+, Ca2+, Mg2+ and NH4 +. NO3 -, SO4 2- and NH4 + were characterized as derived from fossil fuel burning and K+ as an indicator of biomass burning, a common practice in the metropolitan area. Ca2+ and Mg2+ were considered as a result of resuspension of soil and construction. Comparing the ions determined in the wet and dry period, it was found that there was statistically difference between the two periods, with the higher concentrations of ions in the driest period.