Caracterização óptica dos aerosóis sobre a cidade de Maputo

Abstract

The interest in characterizing the optical properties of aerosols in southern Africa, and including Mozambique, has been increasing, due to the great increase in the levels of pollution in the atmosphere and, mainly, given the need to know the quality of the air we breathe. From the analysis of the data obtained in the determination of the optical thickness of the aerosols and the Angström parameter at the wavelength of 530 nm, over the city of Maputo, using a solar photometer (Hazemeter), between 27 August and 25 September 2002 , it was found that, in approximately 50% of the measurements, the optical thickness of the aerosols had a daily average of 0.28 + - 0.20, which means a high level of concentrations of aerosols in the atmosphere. The exponent of the Angström parameter for the same period, had a daily average of 1.10 + -0.26, with a value of 1.23, thus observing that, regarding the size of the aerosols, a mixture of particles is noted fine and coarse fraction, indicating that there are different sources of particles. According to the same data, it was observed that the highest levels of concentration of aerosols, with an optical thickness between (0.8-1.2), were observed in Xipamanine and Hulene, while in the University Campus (Sommerschield-Coop), this proved to be lower (0.0-0.2). The distribution of the size of the aerosol observed in the different points, shows a high value of the Angström parameter (corresponds to the final particles) to predominate in the Hulene and Pandora zone. Therefore, based on these results, it was observed that, although there are areas such as Xipamanine, where large dust movements (corresponding to coarse particles) can be found, the burning of fossil fuels and biomass are the major factors that contribute to the increase in aerosol levels in our urban center.