Qualidade do ar, variação temporal e risco de exposição aos níveis de btex em vias de intenso fluxo veicular na cidade de Fortaleza-CE

Abstract

The purpose of this report was to evaluate the air quality in intense vehicular flow paths in the city of Fortaleza, as well as its temporal variation and its associated risks using as an indicator the levels of BTEX, specifically: to assess air quality by determining the concentrations BTEX present in the atmosphere; investigate the temporal influence on BTEX concentrations collected at different seasons of the year correlated the weather variables and vehicular flow; compare the results and assess the risk to health. Therefore, we selected five locations of vehicular distinct flow in Fortaleza (Av. Aguanambi, Av. Bezerra de Menezes, Av. Abolition of the University Avenue and Rua Marechal Deodoro) and analyzed by period (wet and dry) and shift (morning and afternoon). The results of this study showed that in the rainy period the levels of BTEX composition were higher in the afternoon than in the morning shift, as the Dry Period BTEX funding levels per shift was diverse, it is necessary to emphasize that there were significant expressions the levels of these compounds in relation to the seasonal variation in which the rainy period levels of BTEX composition were higher than in the Dry period and the parameters that most had a closeness between the correlation of BTEX and meteorological variables compounds in the rainy period were radiation and Precipitation. In the Dry Period was radiation for moderate positive correlation and moderate negative correlation of wind speed in which tells us that the wind did not favor the capture compounds in the sampling site in the dry season. Levels of BTEX, the estimated cancer risk for benzene compound in the rainy period ranged from 8,89E-07 1,56E-06 for women and 8,50E-07 1,53E-06 for men and Period dry ranged from 5,76E-08 to 2,19E-07 for women and 7,01E-08 to 2,09E-07 and the hazard ratio for non-carcinogenic compounds (Toluene, Ethylbenzene, m-p-o, Xylene) for the rainy period ranged of 6,45E-06 to 3,66E-05 for women and 6,17E-06 to 3,50E-05 for men since the dry period this index ranged from 1,44E-06 to 4,05E-05 for women and 6,92E-08 to 1,40E-05 for men showing up below the permissible levels at all sampling sites based on limits of some national and international standards, these calculations based on environments and labor hours regime adapted to this study since there is no legislation to the limits of BTEX composition outdoor (external). The results from the correlation of BTEX compounds and vehicular traffic flow were weak correlation Where in the rainy period was r = 0.38 and Dry period was R = 0.42, where the Dry Period was more expressive between variables this correlation. The ratio of the rainy season of the dry period was 1.98 for the benzene compound, 2.47 to toluene compound, 4.63 to ethylbenzene compound and 3.98 for compounds of m, p, o Xylene. Previous studies have shown that is possible to occur phenomena that occurred in this sample in which the pollutant composition is higher in winter than in summer or when the stability of some phenomena in the atmosphere are higher in some periods than others.