Air Pollutant Levels near Expressway: Comparison of Mean Values at Different Conditions

Abstract

Understanding the effectual factors of pollutants levels near expressways is essential andnecessary for planning air pollution prevention program for nearby population and for planning futureexpressway projects. This paper presents the results of a research which compares the meanconcentration values of four gaseous pollutants: CO, NO₂, O₃, and SO₂; and three particulate pollutants:Pb, PM₁₀, and TSP, at different conditions. It determined the factors that can be used to separatebetween high and low concentration level groups. The data used are the air quality monitoring dataof the Chalongrat Expressway in 2001.

Tests for mean concentration difference between groups divided using criteria derived fromstudied factors yielded several factors that can separate between high and low concentration levelgroups. They include time of the day, number of vehicle, and distance from the expressway. On theother hand, factors that do not appear to be good separators are wind speed and wind direction.Moreover, NO₂ is found to be the best indicator of traffic air pollution.

Keywords : Air Pollution / Expressway / Concentration Comparison / Pollutant Factors