SIG aplicado à estimativa de material particulado na cidade de Fortaleza, Ceará

Abstract

In urban centers, the main anthropogenic pollution sources are derived from vehicular traffic and when exists, from industrial activity. This problem make urban air pollution one of the main degradation factors of the population's quality of life. Among the variables that influence the transportation and diffusion of pollutants, can be quoted buildings and weather conditions. Therefore, the study aimed to evaluate the distribution of the levels of respirable particulate matter (RPM) during the rainy and dry seasons, to elaborate a map of air quality of the northern sector in the city of Fortaleza. The study area covers nine locations geographically distributed throughout the city, which are: Escola Estadual Presidente Roosevelt, Centro de Humanidades da Universidade Federal do Ceará (UFC), Centro Acadêmico de Finanças (UFC), Faculdade de Economia (UFC), Habitafor, Praça das Flores, calçadão da Beira Mar, Instituto de Ciências do Mar (UFC) and Paróquia de Nossa Senhora da Saúde. The RPM data was obtained by active sampling (flow pump for air suction) in a 12 hour period. The map of RPM concentration was obtained from a geostatistical interpolation proposal called Ordinary Kriging (OK) worked on in a Geographic Information System (GIS). The produced maps alerts to the RPM levels in the Praça das Flores, Habitafor and Centro de Humanidades, whose concentrations exceeded international standards. In relation to meteorological parameters, the wind and the rain appeared as factors that influence, respectively, in the dispersion and RPM residence time in the atmosphere, being the highest recorded concentrations during the dry season. As a result, the GIS tool has proved to be a satisfactory technical decision support for managers, combining pollution data, urban topography and weather conditions in a geographic database. In this context, the OK based on the exponential semivariogram model was the best one that represented the reality taking into account the conditions of wind and topography of the study area. Thus, the use of these tools in directing urban growth plans is essential to a better urban management.