AN OBSERVATIONAL AND NUMERICAL STUDY OF A SEVERE AIR POLLUTION OVER TEHRAN MEGACITY

Introduction: Nowadays, air pollution is one of the most important problems, leading to serious financial and human health concerns. On the 15th to 17th days of November, 2016 an intense air pollution episode occurred in Tehran, Iran. Materials and methods: In this study, the meteorological data, pollutant concentration, and the data related to this severe air pollution episode, required to implement the model, besides, a brief account, pertinent to the configuration of atmospheric model WRF and air quality model LASAT is presented and certain meteorological quantity are studied. Results: Statistical analysis indicates in this case study, negative wind speed anomaly and positive mean temperature anomaly related to the average 65 years for Novembers. The minimum visibility, is reported for the two days of November 15 and 16. Atmospheric vertical structure analysis shows the temperature inversion at 950 hPa height on November 14th, 2016, it causes stable atmospheric conditions. Conclusions: Running WRF model, with YSU boundary layer scheme, shows that it can well simulate the atmospheric quantities, however, the 10 m wind speed has more errors among the quantities. In this case study LASAT Model is applied for simulation of different pollutant concentrations. The results indicate the underestimation of model by using the output of WRF as atmospheric model is not dependent on the meteorological data, whereas the reference error is driven either from the parameterization, or from the estimation of pollutants emission related to ground level.