Um método para a medição da concentração de carbono elementar (Ce) numa atmosfera urbana

Abstract

Considerable amounts of EC-elemental carbon aerosols are produced in southern Africa in general, and in Mozambique in particular, primarily by human activities such as arson, industrial activities, transport and burning of fossil fuels for production power. The measurement of elemental carbon concentration in the urban atmosphere of Maputo is extremely important to assess the effects of aerosols on the health and climate of the region. Due to the attenuation effect of solar radiation, elemental carbon aerosols can affect the distribution of radiation over the Earth's surface, thus influencing the warming or cooling of the region. Interest in measuring the concentration of elemental carbon in the atmosphere of the city of Maputo 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 data obtained in the determination of the CE concentration over the city of Maputo, using a portable air sampler - MiniVol and a manual densitometer, between 10th September and 10th October 2004, it was found that, in approximately 19% From the measurements, there was an EC concentration above the national standard (65pg/m3) and a daily average of (2.67 +/- 0.26)pgZm , which means a high level of elemental carbon aerosols in the atmosphere. According to the same data, it was observed that the highest levels of aerosol concentration, with a concentration of EC between 2.13 and 7.69pg/m3, were observed in Hulene, while in Bairro Central, this was lower between 0.45 and 1.61pg/m3. Therefore, based on these results, it was observed that, although there are areas such as the University Campus, where large dust movements can be found (corresponding to coarse particles), the burning of fossil fuels and biomass are major factors that contribute to the increased levels of EC aerosols in the urban center.(TRADUÇÃO NOSSA)