Risk Indices for the City of Buenos Aires

The climate and the urban configuration at the urban space level is determinant of the risk related to the capacity of concentrating or diluting pollutants (Zellner, 1995 ; Zellner et al., 1996). We elaborated a risk index based on the direct or inverse relationship between the capacity of concentration of atmospheric pollutants in the urban space and the different variables of urban configuration  and of climate , which are independent:
 

The greater the average height of construction, the greater the time of residence of the gases in the urban space. The greater the width of a street, the greater the volume of air where the gases can be diluted and the better the conditions of turbulence. The standard deviation of height gives an idea of the heterogeneity in height of construction in a certain area of the city, which favours conditions of turbulence and dilution (Figure 1A and Figure 1B to 1D) . These indices are only representative in relative terms, since we have not aimed to estimate the concentration of air pollutants.

From the air quality point of view, the combined situation of persistence in wind direction and in atmospheric stability results in determining high levels of concentration of pollutants. Mazzeo and Venegas (1993) analysed the pollution produced by sources of emission, considering the persistence of certain atmospheric conditions. In this study, we used this concept of persistence of meteorological conditions in order to calculate a weighted annual average of the predominant wind direction with persistence of atmospheric stability. The variable ventilation relates the alignment of the streets with the predominant wind direction.

References

MAZZEO, N. A.; VENEGAS, L. E.; 1993. Normas legales y modelos de calidad de aire. 8a Reunión técnica de desarrollo tecnológico y tecnologías apropiadas para el saneamiento y medio ambiente, Mar del Plata, Argentina.

ZELLNER, M; 1995. Identificación de Areas de Riesgo de Contaminación Atmosférica en la Ciudad de Buenos Aires. Seminario de Licenciatura, Universidad C.A.E.C.E., Buenos Aires.

ZELLNER, M; CAPURRO, A. F. ; JANKILEVICH, S. S. ; 1996. Identificación de Areas de Riesgo de Contaminación Atmosférica en la Ciudad de Buenos Aires. Serie Programa de Investigación y Desarrollo Ambiental Nº 10, Universidad de Belgrano, Buenos Aires.