جستجوی مقالات مرتبط با کلیدواژه « vocs » در نشریات گروه « پزشکی »

The spread of urbanization and industrialization, as well as changes in lifestyle and consumption patterns in recent years, especially in developing countries, has led to the production of huge volumes of pollution in urban and industrial areas. How to plan and manage them is one of the issues and problems in the world today. And if the environment is not taken into account at the same time as the industrialization of a society, not only will economic development not be achieved, but there will be many problems so that sometimes the long-term benefits of an industry are spent on compensation.

The isa descriptive-analyticalstudy. Various steps were taken, including the results of statistical analysis, Delphi questionnaires, analysis of validity and reliability of the research, and extraction of influential factors affecting the performance of the ROP unit of Abadan Oil Refinery in 2019 until 2020. Finally, the results of weighting and ranking of effective strategic parameters in decision-making, decision-making and policy-making processes of different items including factors (components), criteria, sub-criteria, and strategic plans are presented. Using Expert Choice 2000 software, we weighed the parameters, and Cronbach's alpha was determined to be 0.932.

The results of weighting and ranking of effective strategic parameters in the decision-making process and policymaking of various items are presented.Finally, the component of human environment around the refinery with a weight priority of 0.288 in the first rank, the component of natural environment, the HSE component of the refinery with a weight of 0.244 in the second rank, and the components of technical characteristics and conditions of the refinery with a weight of 0.112 were in the third place.

In this case study, we found thatthe greatest need for management was specific to the human environment, such as land use and development plans around the refinery, and the state of air and soil pollution and water resources.

Biogas is obtained by anaerobic decomposition of organic wastes buried materials used to produce electricity, heat and biofuels. Biogas is at the second place for power generation after hydropower and in 2000 about 6% of the world power generation was allocated to biogas. Biogas is composed of 40–45 vol% CO2, 55–65 vol% CH4, and about 1% non-methaneVOCs, and non-methane volatile organic compounds. Emission rates are used to evaluate the compliance with landfill gas emission regulations by the United States Environmental Protection Agency (USEPA). BTEX comounds affect the air quality and may be harmful to human health. Benzene, toluene, ethylbenzene and xylene isomers that are generally called BTEX compounds are the most abundant VOCs in biogas. Sampling of VOCs in biogas vents was operated passively or with Tedlar bags. 20 samples were collected from 40 wells of old and new biogas sites of Shiraz’ landfill. Immediately after sampling, the samples were transferred to the laboratory. Analysis of the samples was performed with GC-MS. The results showed that in the collection of the old and new biogas sites, the highest concentration of VOCs was observed in toluene (0.85ppm) followed by benzene (0.81ppm), ethylbenzene (0.13ppm) and xylene (0.08ppm). The results of the study showed that in all samples, most available compounds in biogas vents were aromatic hydrocarbon compounds.These compounds’ constituents originate from household hazardous waste materials deposited in the landfill or from biological/chemical decomposition processes within the landfill.

The marine coral has a porous outer surface and it has served in the processes such as water treatment systems, removal of carbon dioxide and adsorption of arsenic. Based on the need for cheap and efficient adsorbents, in sampling, the aim of this study, comparison of the efficiency of marine coral powder and activated charcoal in adsorption of volatile organic hydrocarbons was considered. In this experimental research, a certain concentrations of 8 volatile organic hydrocarbons: (para-Xylene, Chloroform, Carbon tetrachloride, tert-Butanol, Pyridine, Acetone, Ethyl acetate and Diethyl ether) was injected into dynamic atmospheric chamber in the NTP (Normal Temperature and Pressure) conditions. Air sampling was performed with the tube containing marine coral powder as well as the tube of activated charcoal, based on the standard method of NIOSH (National Institute of Occupational Safety and Health) and in the same laboratory conditions. Then samples were injected into the gas Chromatograph apparatus and analytical comparison has been done between the amount of adsorption of hydrocarbons by activated charcoal and coral powder-test and Mann-Whitney were done with SPSS V.20.Findings showed that there was a significant difference between the amount of adsorption of Para-Xylene, carbon tetrachloride, tert-Butanol, Pyridine, acetone and Ethyl acetate hydrocarbons by activated charcoal and coral powder (P<0.05(. The amount of hydrocarbons adsorption by activated charcoal was, more than coral powder significantly (P<0.001). Based on the present research, in sampling of used hydrocarbons, the marine coral powder was less efficient than the activated charcoal, and it is recommended that more works be designed about other techniques such as coating of the marine coral powder in order to the improvement of adsorption capacity for volatile organic hydrocarbons.

 In this study, the temporal variations of Benzene, Toluene, Ethyl benzene and Xylene (BTEX) in the atmosphere of Tehran city was investigated. 

 Two air quality monitoring stations, Aghdasieh and Ray, in different locations of the city were selected. Sampling was carried out hourly from Nov 23, 2007 to Dec 22, 2007 in Aghdasieh air monitoring station and from Dec 10, 2007 to Jan 9, 2008, in Ray's air monitoring station by an online BTEX monitoring system. The correlations, repeated measures variance and regressions tests were used for statistical analysis. 

 Results indicated that, concentrations of these compounds were sometimes higher than standard limits and were significantly different in selected stations. However, an approximately similar increasing and decreasing trend was seen among them. In most cases, equations for concentration variations were sinusoidal or fourth-order. 

 According to the results, sinusoidal and fourth-order are most suitable equations for BTEX concentration variations in the ambient air of the city, and the trends of variations are similar in different places of the city.