Conclusion
The main aim of this study was to present a new method for indirect estimation of noise pollution in urban areas where direct measurement is costly and time-consuming. For this, noise pollution was assessed at one of the most crowded districts of Tehran Metropolitan City once by direct measurement and again by indirect estimation. The results of both methods were compared to determine whether they are consistent or not. Comparing noise maps derived from direct measurements (Fig. 5) and indirect estimations (Fig. 6) revealed the fact that darker spots (representing areas with higher noise levels) match in both maps. In other words, both methods lead to a similar result. As conclusion, noise pollution assessment could be done through indirect estimations.