Sharif Digital Repository

Coupled weather forecasting and chemical transport models are useful tools to evaluate air pollution episodes in big cities for the purpose of forecasting and air pollution abatement measures' evaluation. However, large set of accurate data of various sources and modeling calibrations are needed for such complex modeling system to be reliable. The problem becomes more obvious when the model is operated over a domain in which there is a general lack of accurate input data such as emission inventory data. The current study investigates the possibility of model tuning for more accurate prediction of air pollutant concentrations in the city of Tehran in an air pollution episode as a case study.... 

Urban air quality is a major concern throughout the world. The concentration of human activities in a relatively small area puts enormous pressure on urban systems and has led to numerous environmental problems which have created major problems for urban air quality management. The complex nature of air pollution, especially with respect to health impacts in urban areas, has prompted attempts to define the so-called indicators that condense and simplify the available monitoring data to make them suitable for public reporting and decision makers. Several concepts and indicators exist to measure and rank urban areas in terms of their infrastructural, socioeconomic and environment-related... 

Tehran is one of the most polluted cities in Middle East which during winter extremely high levels of particulate matter (PM) occurs due to frequent stable weather episodes. This study aims to identify major sources of PM and quantify effectiveness of possible control measures and strategies during these episodes. The Brute Force Method (BFM) with Community Multiscale Air Quality model (CMAQ) was implemented to estimate the contributions from major local anthropogenic sources on PM levels. In this regard several scenarios including the effect of existing governmental policies and regulations to upgrade vehicles emission standards were investigated. Emission due to the existing condition and... 

In recent years, the city of Tehran has frequently experienced severe air pollution episodes, and the increase in the use of vehicles has exacerbated this critical situation. It is unclear to what extent each vehicle category contributes to the production of pollution during a pollution event. For this purpose, a combination of the weather research and forecasting (WRF) and the Comprehensive Air Quality Model with Extensions (CAMx) modeling systems was used to simulate the distributions of pollutant concentrations over Tehran in a pollution episode from December 3 to 23, 2017. First, the performance of the modeling system was evaluated with respect to the simulation outputs against... 

The present study was conducted to investigate the impacts of retrofitted CNG vehicles on air pollutant emissions in Tehran over a 20 years period using available statistical data, precise automobile tests, data analysis, and LEAP Software. The obtained results revealed an increase in air pollutant emissions including CO (equal to 1030.77 thousand tons), NOx (equal to 1030.77 thousand tons), THC (269.02 thousand tons) and CO2 (equal to 38.43 thousand tons) resulting from utilizing retrofitted CNG vehicles within the studied period. Considering the obtained results, if the current trend of producing retrofitted CNG vehicles continues, a total cost of 435 million USD will impose on the... 

In this study, PM10, PM2.5, and PM1 concentrations were measured from April through September 2010. These measurements were made every six days and on days with dust events using a Grimm Model 1.177 aerosol spectrometer. Meteorological data were also collected. Overall mean values of 319.6 ± 407.07, 69.5 ± 83.2, and 37.02 ± 34.9 μg/m3 were obtained for PM10, PM2.5, and PM1, respectively, with corresponding maximum values of 5337.6, 910.9, and 495 μg/m3. The presence of the westerly prevailing wind implied that Iraq is the major source of dust events in this area. A total of 72 dust days and 711 dust hours occurred in the study area. The dust events occurred primarily during July. The longest... 

There is limited evidence for short-term association between mortality and ambient air pollution in the Middle East and no study has evaluated exposure windows of about a month prior to death. We investigated all-cause non-accidental daily mortality and its association with fine particulate matter (PM2.5), nitrogen dioxide (NO2), and the Air Quality Index (AQI) from March 2011 through March 2014 in the megacity of Tehran, Iran. Generalized additive quasi-Poisson models were used within a distributed lag linear modeling framework to estimate the cumulative effects of PM2.5, NO2, and the AQI up to a lag of 45 days. We further conducted multi-pollutant models and also stratified the analyses by... 

Atmospheric aerosols affect the Earth's climate, air quality, and thus human health. This study used the Aerosol Optical Depth (AOD) and the Ångström exponent to cluster different particle types over the Lake Urmia Basin. This classification found desert dust and marine (mixed with continental or local-pollution aerosols) as two main aerosol types over the region, while their sources are not well defined. Although different air masses and wind circulation over the study domain in varied months can help to distinguish aerosol sources, measurements are crucial for a complete evaluation  

There have been many previous works to determine the determinants of housing prices. All of these works relied on a relatively small set of data, mostly collected with the help of real estate agencies. In this work, we used web mining methods to generate a big, organized dataset from a popular national brokerage website. The dataset contains structural characteristics of more than 139,000 apartments, alongside their location and price. We provided our full dataset for the article, so that other researchers can reproduce our results or conduct further analyses. Using this dataset, we analyzed housing prices of Tehran in order to identify its major determinants. To this aim, we examine the... 

One of the significant challenges in urbanization is the air pollution. This highlights the need of the green city concept with reconsideration of houses, factories, and traffic in a green viewpoint. The literature review confirms that this reconsideration for green space has a positive effect on the air quality of large cities and to reduce the air pollution. The purpose of this study is to evaluate the annual vegetation changes in the green space of Mashhad, Iran as a very populated city in the middle east to study the air pollution. To investigate the relationship between the air pollution and vegetation, the Landsat 8 satellite images for summer seasons of 2013–2019 were used to extract... 

Natural ventilation has been used to increase indoor air quality, remove pollutants, and remove heat absorbed in the building structure. Some architectural features such as wind-catcher systems are used to induce airflow into buildings, and openings equipped with louvers are employed to reduce solar daylight while allowing natural ventilation. Earlier studies on ventilated louvers and wind-catchers have shown the impact of the louvers’ opening positions and slat angles. However, their combination with each other has been less studied. This paper presents CFD simulations of cross-ventilation in a generic isolated building integrated with a one-sided roof-top wind-catcher and the outlet... 

In the recent researches HVAC with a based desiccant dehumidifier with a low ambient impact is more efficient in comparison to the traditional systems. Hybrid desiccant cooling systems can be used to control indoor air quality in buildings. This paper presents an integrated energy, entropy and exergy analysis of a hybrid desiccant cooling system compare to a compression system based on first and second laws of thermodynamic. The main objective is the use of a method called exergy costing applied to a conventional compression system that has been chosen to provide the proper conditioned air for a building in hot and humid condition. By applying the same method for the equivalent hybrid... 

Aerosol measurement is used in a variety of fields such as nanotechnology, materials science, pollution monitoring, air quality measurements, combustion and engine exhaust analysis, inhalation toxicology, and medical studies. One of the most prevalent methods for aerosol measurement is to use electrical mobility. An electrical mobility spectrometer (EMS) is used to measure aerosol particles size distribution ranging from 10-1000 nanometers, under the influence of an electric field. The accuracy of this distribution is influenced by flow conditions, the geometry of the EMS, the electric field, and the number of electrode rings. In this work, a multi-channel EMS is studied using computational...