Foreword
The Environmental Impact Assessment (EIA) notification of May 4, 1994 of the Ministry of Environment and Forests (MoEF), Government of India, makes it mandatory to carry out EIA study before certain categories of industries are sited, or an existing industry is expanded.

Air being an integral part of environment, the proponents must demonstrate the attainment of satisfactory ambient air quality in the vicinity of their source complex. Attainment of satisfactory air quality is generally predicted through dispersion modelling. The present practice for ambient air quality predictions is through application of Gaussian Plume Model and its available variations. The experience so far, has shown that, at times, the model has been used incorrectly, and the values of various parameters, required for modelling, are adopted from other countries without understanding their applicability in Indian context. There is an immediate need to evolve guidelines for conducting air quality modelling for inclusion in EIA procedure so that a uniform and acceptable procedure for modelling is available.