Influência dos cânions urbanos, tráfego veicular e variáveis meteorológicas na concentração de NO² em área com intenso processo de verticalização (Fortaleza – CE)

Abstract

The world population and have increased rapidly in recent decades. This growth, which occurs mainly in a disorderly way, has been responsible for a number of environmental impacts. Air pollution is one of the main problems related to this growth and is pointed out by the World Health Organization as the main environmental cause of death in the world. The increase in vehicular traffic and the presence of industries in urban agglomerations represent the main contributions to the degradation of air quality. In addition to this, there are unfavorable conditions for the dispersion of pollutants caused by the characteristics of the urban surface (roughness, type of material, etc.), such as those observed in urban canyons, nvironments formed by the walls of two buildings and the soil between them. The objective of this work is to evaluate the concentrations of nitrogen dioxide (NO2) in an area with an intense verticalization process, aiming to identify the influence of different degrees of depth (classes) of urban canyons, traffic volume and meteorological variables in concentrations of the analyte. To this end, 3 urban canyons of each class present in the study area (canyon avenue, regular canyon and deep canyon) in the Meireles neighborhood, and 3 control points were selected in the Varjota neighborhood, an area with low buildings and where the wind flow receives lower resistance. Five sampling campaigns were carried out using passive samplers that remained at collection points during the period of one week in the months of March, May, July, September and October/November. The vehicular traffic data was obtained with the Municipal Authority of Transit and Citizenship of Fortaleza, and the meteorological data with the National Institute of Meteorology (INMET). The analysis of the results was done using descriptive and inferential statistics. It was observed that the vehicular traffic has a greater impact on the concentrations of NO2, being responsible for a spatial variation of the concentrations. The NO 2levels presented an inversely proportional behavior to the depth of the urban canyons, this in average terms, being this result related to its effects on the meteorological and climatic properties of the urban atmosphere, but mainly to the fact that the avenues of canyons have greater volume of traffic than the deep canyons studied. The meteorological variables presented antagonistic effects on the concentrations of NO2 between some sites, suggesting the variation between the predominance of emission/local production or transport of adjacent areas.