Análise do material particulado na área central da cidade de São Carlos-SP através de técnicas espectroanalíticas e avaliação multidimensional de séries temporais

Abstract

Due to the worldwide trend of industrialization and urbanization, air pollutants are emitted large quantities on a global scale, particularly in developing countries, which produces adverse effects on human health by causing health problems such as respiratory and lung diseases. In view of this scenario, the objective of this research was to study the PM10 particulate matter, collected in the city center of São Carlos, through the analysis of multidimensional time series and spectral analysis. The collections were from the collection period from 2014 to 2015 (daily collections) and from 2015 to 2017 (collections on alternate days), specifically at Praça dos Voluntários. In the process of analysis of multidimensional time series, a web - based data visualization system was developed with the help of the Java Script and D3 libraries to support the evolutionary analysis of atmospheric particulate matter (PM10) collected in the city. The samples were collected using the large volume sampler, in the time of 23 hours and 30 minutes. The values obtained in the monitoring from 2014 to 2017 clearly showed a decrease of the pollutant PM10 in the atmospheric air of the city, compared with data from historical records of the campaign from 1997 to 2006. This decreasing trend in PM10 concentrations may be due to an increase in strict compliance with State Decree No. 59113 of 04/23/2013, which requires the control of air pollution. For the spectroanalytical analysis, samples collected in the period from 2014 to 2015 were directly analyzed by WD-XRF, identifying the following elements: Al, Ca, Ce, Cl, Fe, K, Mg, P, S, Si , Ti, V and Zn; and for LIBS (Ba, Ca, Fe, K, Mg, Na, Si and Ti) for qualitative purposes. For quantitative analysis, the elements Al, Ba, Ca, Fe, K, Na, S and Zn were subjected to extraction with extractive acid solution (HNO3 and HCl) and determined by ICP OES. The concentrations of these elements presented spatial variations (ng m-3), which were significantly higher for Al (19.0), Ba (13.6), Ca (20.0), Na (27.0), S (37.1) and Zn (9.5) in winter; in autumn, to Na (26.4); in the spring, for Fe (11.6), K (13.1) and S (25.3); and summer did not show high concentrations in the comparison between the seasons of the year. Using the mathematical model (PCA), statistical model (Pearson) and the enrichment factor equation (EF) in these WD-XRF, LIBS and ICP OES results, it was possible to trace the possible origins of these chemical elements in collected atmospheric air in the city.