Author(s)

L. Bontempi, M. L. Ruello & G. Fava

Abstract

An in-situ field study was conducted to measure the outdoor pollutant concentrations necessary to design the ventilation-filtration system and improve the indoor air quality of a public building. The area of study is located in the flat terrain of the Italian Po valley, near a traffic-congested highway and surrounded by an industrial factory and many farms. The quality of the ambient air was evaluated monitoring NO2, toluene and xylenes concentrations, and was compared with that in urban atmospheres and related to traffic emissions. Measurements of pollutant were performed with passive diffusion samplers with the aim to test the hypothesis that the highway contribution to ambient air quality varies with the logarithm of the distance. The toluene/xylenes ratio measured at the building site and at the highway source ratio suggested that beside vehicular emission, industrial and farming sources were governing the volatile organic compounds in the area. The present study confirmed that NO2 concentration at a nearby highway varied linearly with the logarithm of the distance from the highway, but the slope found for this regression was somewhat steeper than those reported in the literature for urban conditions. The reason for this has not been related to augmented atmospheric dispersion differences. Instead, the presence of hydroxyl radicals and volatile organic compounds of either agricultural or industrial origin may affect a complex ozone-hydrocarbon reactivity. The results delineate the pollutant site ratio and the traffic equivalent distance as useful parameters for the source emissions characterisation and the selection of an effective control technology. Keywords: traffic emissions, environmental profiles, source emission ratio, equivalent distance, V.O.C. reaction kinetic.

Keywords

traffic emissions, environmental profiles, source emission ratio, equivalent distance, V.O.C. reaction kinetic.