Analysis of Air Pollution Using the Flow Pattern Based on Averaged Wind Vectors

—Application of the Technique to Ambient SO₂ Concentrations and Winds in Chiba-Seaside Area—

Abstract

A technique for analyzing air pollution by using the flow patterns based on averaged wind vectors was developed. To make the flow patterns, the determined data at the municipal monitoring stations were classified by two methods, one is based on relationship between ambient SO₂ concentration and wind direction, and the other on the wind direction crossing table.
The technique was applied to analyze the characteristics of a high SO₂ concentration in the air over the southern district of Chiba City in the Chiba-Seaside Area. The results showed that SO₂ concentration over the district almost always increases when the wind blows from SSW or WSW direction. This tendency was observed even under the windy weather when the atmospheric stability was nearly neutral, and no unusual temporal or seasonal deviations was found in this tendency.
The above results suggest that the high SO₂ concentrations were caused by the complex emission sources in the Keiyo Industrial Zone.