Sharif Digital Repository

Particuale matters, as a criterion for evaluationg the air quality, have been one of the most important air pollutants through the last decade. Considering the adverse health effects of particulate matters, the importance of monitoring pollutant’s concentration is inevitable. While there are monitoring stations for evaluating the air quality, our knowledge is so limtted since there are few stations working, so there is a spatial and temporal gap. On the other hand, chemical transport models and remote sensing provide us a better chance to track the air quality thoroughly. Since chemical transport models are our only way of filling the gaps, they should be rigorous and accurate. In this study... 

Homogenous carbonylation of methanol is a major way to acetic acid. In this study central composite design (CCD) at five level (-1.63, -1, 0, +1, +1.63) combined with response surface methodology (RSM) have been applied to optimize carbonylation of methanol using ruthenium promoted iridium catalyst in homogenous phase. The effect of seven process variables including; temperature, pressure, iridium, ruthenium, methyl iodide, methyl acetate and water concentrations as well as, their interactions were modeled. The determined R2 values greater than 0.9 for the rate, methane, carbon dioxide and hydrogen formation data, confirmed quadratic equation properly fitted obtained experimental data. The... 

Since Iran is a part of Afro-Asian belt of deserts, 21 percent of its area belongs to desert lands. By the increasing number of dust storms in western adjacent countries dust particle concentration’s value has been critical. PM10 modeling and finding out dust origins can extremely help to manage methods by decision-makers to control dust from the origin. HYSPLIT modeling tool is benefited to get to this aim. In this study metropolises which hardly confront air pollution according to EPA statement were selected. HYSPLIT was calibrated and validated by comparing the results with measurement stations. According to the point that that particles were transported from western parts of Iran,... 

Recent progress in developing Artificial Neural Network (ANN) meta-models has paved the way for reliable use of these models in the prediction of air pollutant concentrations in urban atmosphere. However, improvement of prediction performance, proper selection of input parameters and model architecture remain key challenges to their practical use. This study’s main objectives are: selecting proper input parameters for ANN meta-models, optimizing the ANN models to achieve the most accurate hourly prediction for a case study (City of Tehran), coupling the ANN method with filtered input data and evaluating its privilege. In the current study the ANNs were constructed to predict criteria... 

Mobile Sources are the main source of air pollutant emission in Tehran, the capital city of Iran. Everyday thousands of vehicles commute in roads and highways. Unfortunately, People are exposed to high level of particulate matter and gaseous contaminants in automobile cabins. Even though this environment is exposed to high pollutant concentration emitted by on-road vehicle, In comparison with other built environment, in-cabin commuter exposure and its key parameters has never been quantified. In general, this work entails measurement of in-cabin air quality, predicting mathematical models for calculating Air-Exchange-Rate (AER) in vehicles and on-road vehicle emission measurement. Our... 

Particulate matter (PM) with aerodynamic diameter less than 2.5 micron (PM2.5) is cause of dangerous diseases, like respiratory and cardiovascular and it is one of the main causes of poor air quality in the city of Tehran. Despite the importance of the issue, there is no complete information on the chemical components of the PM2.5 in Tehran. In this study, 24 samples of particulate matter PM2.5 collected during one year in each 6 days at the station of Air pollution monitoring station related to Air Quality Control Company (AQCC) at the Sharif University of Technology. Chemical analysis was performed on samples to determine the composition of particulate matter include organic carbon,... 

Detetrmination of particulate matter (PM), as one of the most important pollutants in big cities, requires extensive system of monitoring stations. Remotely sensed atmospheric data due to their large spatial coverage and frequent observations are emerging as an important addition to conventional ground based atmospheric monitoring. In this regards this study presents an approach to analyze the relationship between PM10 (particles with aerodynamic diameter less than 10 μm) and the satellite product of aresol optical depth (AOD), which is the measurement of the extinction of light due to interferences with particulate matter. In the current study AOD is observed by Moderate Resolution Imaging... 

This study aims to estimate the emission rate of Volatile Organic Components (VOCs) and hazardous air pollutants from the surface of evaporation ponds in oil and gas upstream industries. With respect to the irrecoverable consequences of such emissions, the emission of air pollutants in the oil and gas upstream industries are alarming. Hence, estimation of the pollutants’ emission and surface pollution monitoring are needed for controlling and decreasing of air pollutants in oil and gas upstream industries and also presenting and performing suitable and efficient solutions. The studied ponds in this research include 4 ponds in the oil and gas upstream industries which have been used for... 

Due to their adverse effects on human health and the environment, PM2.5 has been identified as one of the most important pollutants in Tehran. Considering the heterogeneous land use of this city, insufficient information on the amount and chemical components of these particles in its various regions, as well as lack of accurate information about the contribution of each source in the production of pollutants, this research investigates the concentration of fine particulate matter and its constituents in four stations of Tehransar, Sharif University of Technology, Shahid Mahallati and Shahriyar and studies their sources. Initially, the pollutant mass concentration and concentration of its... 

Air pollution is treating civilians of megacities. One of the most dangerous pollutants is particulate matters with the aerodynamic diameter less than 2.5 microns. For reducing the concentration of these particles in Tehran’s atmosphere, it is necessary to investigate the source’s contribution and emission factors. Receptor models such as Chemical Mass Balance are used for source apportionment analysis. The major input of these models is the source profile. Since vehicles are the only source of pollutant in the urban tunnels, these tunnels are ideal media in order to investigate the vehicle’s source profile and emission factor. This project aims to determine the source profile and the... 

Considering the increase of particulate matters in the last three decades in Tehran, many endeavores have been made in order to determine and recognize the contributing factors in the production of particulate matters. Although emission source of particulate matters is available in the form of emission inventories, these emission sources are not accurate and they need to be modified. By modeling the air pollution we can determine the relationship of pollution source and their effect on air quality.Modeling air pollution helps us to determine the relationship of pollution sources and their effect on air quality. Air pollution managers use models to determine the contribution of emission... 

Obtaining particulate matter (PM) concentration is very important in epidemiological studies. Measurement at the ground levels has been used as an accurate method to obtain PM levels. However, these measurements are more indicative of a small area around the stations than a whole region. Usually, limited space coverage and irregular distribution of air quality stations at the ground level is a restriction in the studies of air pollution and its effect on human health and environment. In this regard satellite measurements have been used for indirect estimation of PM concentration at ground levels. However, the correlation between satellite measurements and ground based data is affected by... 

The concentration of air pollutants in the environment is variable according to different factors, including distances from main sources. Vehicles in streets and highways are one of the most important sources of the air pollutants. Hemmat highway is one of the most significant highways in Tehran with traffic congestion of 15000 to 18000 vehicle/hour. In this research, the concentrations of PM10 and CO were determined in different distances of Shahid Hemmat highway and the relationship diagrams of traffic and meteorology to the amount and emission of air pollutants were drawn. The concentration gradient diagrams showed exponential decay, which demonstrated that more than of 50% of air... 

Mobile Sources are the main source of air pollutant emission in Tehran, the capital city of Iran. Everyday thousands of vehicles commute in roads and highways. Unfortunately, People are exposed to high level of particulate matter and gaseous contaminants in automobile cabins. Even though this environment is exposed to high pollutant concentration emitted by on-road vehicle, In comparison with other built environment, in-cabin commuter exposure and its key parameters has never been quantified.
In general, this work entails measurement of in-cabin air quality, predicting mathematical models for calculating Air-Exchange-Rate (AER) in vehicles and on-road vehicle emission measurement. Our... 

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... 

In this study different prediction models including linear mixed effect (LME), multi-variable linear regression (MLR), gaussian process model (GPM), artificial neural network (ANN) and support vector regression (SVR) were developed using satellite AOD product - with spatial resolution of 3 km – coupled with various auxiliary parameters to estimate ground-level PM2.5 over Tehran. The influence of site effect term on performance of LME models was evaluated using random intercept for monitoring sites. Results showed LME models without this term were able to explain variabilities of PM2.5 in ranges of 60 – 66% and 35 – 41% during model fitting and cross-validation (CV), respectively. By... 

Particles with aerodynamic diameter of less than 10 μm can effectively pass through respiratory system and deposit on pulmonary areas wich cause adverse health effects. These particles are divided in to coarse particles (diameter: 2.5 to 10 μm) and fine particles (diameter < 2.5 μm). Fine particles can be more harmful for human’s health and harder to remove by air pollution control machines compare to coarse particle so it is crucial to find methods to enlarge the size of these particles. In this regards common methods such as utilizing electricity are costly and not efficient enough. Hence other economical and efficient methods such as using condensation are eamined. In this study the... 

Tehran possesses various environmental crises due to excessive population growth, a huge increase of vehicles and heavy concentrated industries. One of the most important concern is air pollution. Spectral Analysis by discrete Fourier transform are described and applied to harmonic analysis of time series for detecting Present periodicities.
The current work proposes an approach for the determine the contribution of different frequencies to the data variance using air quality measured data. In this research, we present a comprehensive review of methods for spectral analysis of nonuniformly sampled data. Because of The air quality data in Tehran have irregular sampling periods and...