Effect of atmospheric and operational variables on dispersion of bauxite particulates at Mormugaon Port, Goa, India

Abstract

During material loading to the ship or unloading from the ship, fugitive emissions takes place which leads to major air pollution at the port and nearby area and leads to health problems of the people in the area. Majorities of the studies on dispersion of pollutants in the atmosphere are carried out for the point and non point emissions at high level (more than 10 m from sea level). This paper presents the detailed simulation studies on effect of various operational and meteorological variables on dispersion of particulates released due to fugitive emissions during bauxite cargo handling operation at the port. During the said operations, the fugitive emissions of bauxite take place near sea surface (2 to 5 m above sea surface) as compared to releases from stack or chimney. In this work investigation was aimed at to understand key elements that influences the diffusion of the particulates emitted due to fugitive emissions during the said operation at the port. Identification of key elements that influences the diffusion of the particulates enables the authorities to take appropriate preventive measures in order to reduce the emissions at the source. The key elements considered for this study were wind velocity, ambient temperature and moisture, water content of bauxite, the distance between the crane and barge. The AERMOD software was used to carry out the simulation studies. The results revealed that wind velocity and bauxite water content are key elements which affect the dispersion significantly. At low altitude (0.5 m to 5 m from sea level) in atmosphere, change in ambient temperature and moisture does not affect the dispersion of particles. Variation in drop altitude from 0.5 m to 3 m does have significant effect on particle dispersion near the source (within 50 m); however, it does not affect the dispersion away from the source.