Author(s)

K. Ourtirane & R. Alkama

Abstract

The aim of the study is to analyse the amount of atmospheric pollution emitted by vehicular traffic in the road tunnel of Kherrata which is situated between the towns of Bejaia (36o45’N, 05 o06’E) and Setif (36 o11’N, 05 o15’E) in Algeria. The geometric characteristics of the tunnel are: the length (5865.25 m), the height (6.5 m) and the mean slope (5.1 %). Captors of particulate pollution were installed, they permit the measurement of the suspended particles concentrations at any time. Moreover, we installed a wash system operating by remote control in order to count the number of vehicles crossing the tunnel during the same period. The vehicles crossing the tunnel were classified according to the following characteristics: type (bus, lorry, car), fuel (diesel, essence) and direction (descendant, climbing). In order to find possible relationships between atmospheric pollutants and the sources (road traffic), taking into account the type, the fuel and the direction, we applied the statistic methods of correlation-regression and principal component analysis. To estimate the amount of pollution at the emission (exhaust pipe), we use a mathematical model of pollution dispersion: the box model. We find that the number of vehicles is related significantly and linearly to increase of atmospheric pollutants in the tunnel, the vehicles using diesel as fuel emit more pollutants. Taking into account the slope parameter, we remark that the descendant vehicles emit less pollutants than the others. With the help of box model, we find a significant correlation (R=0.827) between the pollutants measured and the pollutants estimated in emission (exhaust pipe).

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