During planning stages, when noisy activity has not been implanted or while evaluating operation changes, it is necessary to find an environmental noise mapping prediction tool for future scenarios. When an activity is already implanted, it is possible to measure noise emissions, but this is expensive, so prediction tools can also be useful. Because of these reasons, for the last 10 years, as a response to the increasing concern for noise pollution in developed countries, several simulation models have appeared to predict noise levels outdoors. Many of those models are customized for specific noise sources.
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