Sharif Digital Repository

In recent years, in Tehran, air pollution became one of the major problems in this city. Among air pollutants, particle matter (PM) is very important in aspect of negative effect on environment and human health. Effective control of these particles requires correct determination of rules and adopting appropriate managing policy which are mostly very cost-consuming. Rules determination and adopting appropriate policy is very challenging in Tehran due to lack of sufficient information about concentration dispersion of such particles. The aim of this study is to recognize the factors of producing PM10 and appropriate understanding of changes of particle matter concentration of Tehran by... 

Tehran air quality is facing a real crisis. Reports of pertinent organizations show air quality is deteriorating in recent years and unhealthy days are increasing. As a result, study and planning in order to change this trend and moving toward improving air quality is a necessity. On the other hand, in order to make proper decisions and choosing effective approaches considering cost-effective attribute and legal, temporal and budget restrictions, selecting the right tool is essential. Air quality models are the tools which in a cost saving manner and reasonable time can provide the required results for researchers, decision makers and legislators. An applicable model correspondent with urban... 

In recent years, dust storms have turned into one of the most prominence environmental issues, existing in Tehran. The infiltration of dust through west borders has led to significant increase in the concentration of Tehran’s pollutants. The main abroad source of these dusts are deserts located in Middle East. The contribution of Middle East deserts in daily concentration of PM10, without the inclusion of local emission sources, was analyzed in previous studies. In this study, we analyzed the contribution of dust storms, formed in Middle East, in Tehran’s PM10 and PM2.5 concentration, using CMAQ model. Dust periods between 2012 and 2014, was identified using observation data and satellite... 

In atmospheric studies, chemical transport models are formulated to simulate the spatial and temporal distribution of pollutant concentrations. However, the performance of these models is strongly dependent on the input parameters such as emissions. Inverse modeling is a widely used mathematical approach for estimating model parameters by minimizing the discrepancy between model output and observations. For air quality studies, inverse modeling is often used for emission inversion as emissions are associated with significant amount of uncertainties.This research aims to estimate optimal values for anthropogenic PM2.5 emission through a four-dimensional variational (4D-Var) inverse modeling... 

This study aims to investigate the effects of urban design and development on Tehran's air quality in calm conditions. Known strategies such as bright roofs and facades, urban development, and modification of the building density are in the focus. The WRF model coupled with Single-Layer Urban Canopy and Building Effects Parametrization canopy schemes were used to predict weather parameters. SMOKE and CMAQ models computed the concentration of pollutants in the city. Urban canopy schemes had correlation coefficients and an index of accordance of about 0.9 and the mean bias was lower than 2. Wind prediction had a lower correlation. The BEP scheme reduced the mean bias for temperature and... 

Every year, air pollution is causing immense harm to humans and the environment. To cause Air pollution, several factors are involved. Among these are the sources of emissions such as factories, power plants and Cars, meteorological factors such as temperature and wind speed and geographical conditions such as altitude, postal and looming around the area, land slope and soil type region. The aim of this study is to identify factors that affect the ozone concentration in Tehran, which could help identifying other secondary pollutants. For this purpose, a combination tailored to the geography of Tehran using CMAQ-WRF-SMOKE-made programs. This model includes four intervals each of which lasting... 

In the current study, the dispersion of four major air pollutants, sulphur dioxide, nitrogen oxide, carbon monoxide, and particulate matter from gas flares of an oil field, in Iran, was investigated for year 2011 by application of a conventional steady state Gaussian dispersion model, AERMOD. Two scenarios were applied in modeling, first application of flare parameters based on technologies that exist and the other one using new technologies in flares such as steam assisted with better combustion efficiency. Due to the complexity of meteorological parameters in modeling area, CALPUFF model was used in this study. CALPUFF which is a more advanced model that considers the effect of... 

In recent decades, local, regional and national research programs have discovered stormwater runoff as the principal cause of water pollution in most urban areas. To solve urban stormwater runoff problems, we should use revisory measures. This is possible by using Best Management Practices (BMPs). BMPs are innovative technologies to reduce the movement of pollutants from land into surface or groundwaters, in order to protect water quality within natural and economic limitations.Three types of BMPs are discussed in this study; swale, bioretention systems and pond. They have different installation requirements, costs and pollutant removal efficiency. The main objective of this research is to...