نتایج جستجو برای: the anthropogenic sources of heavy metals include traffic emission vehicle exhaust particles
تعداد نتایج: 22850889 فیلتر نتایج به سال:
background : airborne particulate matter is one of the most important atmospheric pollutants. tile sources of particulate matter in the atmosphere are divided into two groups; 1) natural sources and 2) anthropogenic sources. the important components of airborne particulate matter and invarying concentrations are the ubiquitous components of the lower atmosphere. heavy metals are mainly emitted ...
Backgrounds and Objectives: Quantity of trace metals in the wet precipitation can illustrate the environmental pollution of different urban areas. Up to now, there is no study regarding the chemistry of wet precipitation in Tehran .The objectives of this study are: measurement of heavy metal concentrations and identification of the main factors affecting the heavy metal concentrations in wet pr...
This study was set out to characterize particulate emissions from transportation diesel engine in terms of heavy metals. The exhaust particulates from Mahindra DI engine were collected and analyzed at four different engine operating conditions namely idling, 40%, 70% and full load. It was found that as the load increases from idling to full load, the heavy metal content in particulates graduall...
in this research we have studied the effect of some transition-metals (cu, ag and au) substitutions on two-electron reduction potential of flavins by application of dft method. all geometries have been optimized at blyp level of theory and “6-31+g** + lanl2dz” mixed basis set. the frequency job at the same method and basis sets has been performed to obtain gibbs free energy of compounds. it h...
Airborne particulate matter (PM10 ) was collected from the atmosphere of the city of Isfahan. The concentration of heavy metals and anions associated with airborne particulate matter were determined using atomic absorption spectrometric and ion chromatographic techniques. A comparison was made between the variation in the concentration of PM10 and that for heavy metals and...
this study purported to compare and contrast the use of self-mention and evidentials as two mtadiscourse features in opinion columns of persian and english newspapers. the theoretical basis of this study is the idea that metadiscourse features vary across cultural boundaries. for this purpose, 150 persian and 150 english opinion columns were collected based on three factors of topic, audience a...
Rockets are the only direct anthropogenic emission sources into the upper atmosphere. Gaseous rocket emissions include CO, N2, H2, H2O, and CO2, while solid rocket motors (SRM) additionally inject signi¦cant amounts of aluminum oxide (Al2O3) particles and gaseous chlorine species into the atmosphere. These emissions strongly perturb local atmospheric trace gas and aerosol distributions. Here, t...
exhaust emissions contribute greatly to air pollution, the social cost of which may occur as danger to human health, attracting huge medical expenses, causing absenteeism and hence loss of productivity. these are incentives to reduce exhaust emissions to the barest minimum. two major cities in ghana, accra and kumasi, are struck by vehicular traffic jams especially during rush-hours and are gra...
asymmetric membranes are widely used in many industrial membrane separation processes. the major advantage of membrane filtration over the conventional process is its ability to remove a wider spectrum of particles without using any chemicals. hollow fiber configuration offer many advantages over flat-sheet or tubular membranes. the spinning process of hollow fiber may look simple, yet it is te...
Background and Aim: Heavy metals in the surface soils of cities caused by various sources (such as traffic, industrial emissions, erosion from buildings, etc.) can be accumulated through inhalation; ingestion and dermal contact in the human body and endanger human health. The purpose of this study is to evaluate the potential of ecological risk and human health risks of some heavy metals in roa...
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