Air dispersion modelling uses mathematical formulae and computer simulations to characterise the atmospheric processes that disperse air pollutants emitted by a source. Based on the type of emissions and the meteorological conditions inputted, the model can be used to predict the concentrations of pollutants at selected receptors downwind of the source location. Through our ongoing air monitoring programmes, we collect extensive amounts of data from specific sites and situations that are useful inputs to such models devised by our associate modellers.