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

Air pollution is one of the problems in many countries posing serious challenges the world is facing today. This is a global public health and environmental issue with multiple facets; it affects all aspects -human health, development, economy, land use and the environment. Although industrial revolution has been a great advancement in human life in terms of technology, societal development, creation and provision of multiple services, it has also resulted in the production of large quantities of unpleasant substances the atmosphere. It is no doubt that worldwide urbanization and industrialization are escalating at a high rate and reaching unprecedented proportions in many countries. In this article, we revisit the state of air pollution over southern Africa and assess the extent to which this can impact on the regional environment. The study is qualitative but also employs a blend of quantitative and qualitative evidence on the status of Air Quality (AQ) over southern Africa. The subcontinent is now a significant source of atmospheric and environmental pollution, having transformed from a rural to one of the more developing regions in the world. There is an influx of particulate and gas pollution from both local and remote sources. Prominent hotspots can be observed on satellites for Nitrogen Oxide (NOx), Particulate Matter (PM) and Biomass Burning (BB) emissions around active areas. Depending on the nature of pollutant generation and amount, there are often differing levels of exposure to certain toxic elements, some of which are more harmful to human life. Increase in seasonal/annual pollution, in accordance with continued human development and industrial revolution can have a dire effect on the region, especially considering the growing African population. Comprehensive long-term AQ management programs are therefore needed to ensure that tolerable pollution levels are not exceeded, and that population exposure is taken care of.

Today, a lot of research work is carried out in the vegetable oil based fuels which are the blended renewable fuels derived from vegetable oils or the oxygenated fuels which could effect in reduced Carbonaceous emissions. This experimental study investigates the impact of Silicon dioxide (SiO2) nanoparticles as additives on the performance and emission parameters of a diesel engine running on castor oil blends.

Castor oil is a renewable source of biodiesel, but it has limitations such as lower calorific value and higher viscosity compared to conventional diesel. To overcome these limitations, SiO2 nanoparticles were synthesized and characterized. Tests were conducted on a single-cylinder diesel engine under various load conditions using different fuel blends.

Results shows that the addition of SiO2 nanoparticles improved the engine's performance by increasing brake thermal efficiency by 25% and reducing specific fuel consumption by 9%. Carbon monoxide emissions (CO) were decreased by 25%, Hydro Carbon emissions (HC) decreased by 52% with SiO2 nanoparticles while a marginal percentage of NOx was also observed.

This study demonstrates the potential of SiO2 nanoparticles as additives in enhancing the performance and reducing emissions of diesel engines using castor oil blends, contributing to the development of sustainable transportation.

Air pollution in cosmopolitan cities is increasingly becoming unprecedented with attendant effects on human and biophysical attributes.

The study was carried out at Federal University of Technology (FUTO) and environs in the southeastern Nigeria. Some ambient air quality parameters (CO, CO2 , NO2 , CH4 and noise) were sampled and measured at seven unique locations (OR, ER, FR, EJ, IM, FM and FJ) with multi sampler devices, using air differential technique during the morning, midday and evening periods.

The average pollutant results show increased concentrations at the different locations when compared to Occupational Safety and Health Administration (OSHA) than Federal Ministry of Environment (FMEnv) thresholds (FMEnv>CO2 <OSHA; FMEnv>NO2 <OSHA; FMEnv>CH4<OSHA). However, concentrations of CO and Noise in FR and FJ were relatively higher than concentrations observed in other locations (CO: FR [6.4 mg/m3 ] and FJ [4.2 mg/m3 ]; Noise: FR [96.8 dB] and FJ [95.7 mg/m3 ]) respectively.

The significant increase could be attributed to continuous vehicular emissions and presence of make-shift activities in these locations. However, predictive model suggests that given the meteorological conditions and perceived anthropogenic activities over time, OSHA threshold could be evidently compromised.

Human skin gas is known as traces of gas emanating from the human skin. Exogenous chemicals such as toluene may be released from the skin surface when absorbed into the body. However, dermal emission of toluene has not been fully determined in relation to inhalation exposure.

This study aimed to characterise the mechanism of toluene emanating from the skin surface of healthy volunteers in relation to inhalation exposure.

Dermal emission flux of toluene was determined in healthy volunteers employing a passive flux sampler and gas chromatography-mass spectrometry.

The dermal emission of toluene occurs when toluene is absorbed by inhalation. The half-life obtained from the decrease in the dermal emission flux suggested the time-course of the dermal emission corresponds to that of the blood concentration. The whole-body emission rate of toluene was estimated to be 9.9% of the uptake rate by inhalation exposure. This suggests the toluene is excreted approximately 80% through urine, 7% - 14% by exhaled air, and 10% from the skin surface.

This demonstrates that dermal emission is a newly discovered route of excretion of toluene from the human body and that dermal toluene might indicate the individual biological susceptibility to inhalation exposure to toluene.

Most vehicles with over 20 years of age have low combustion efficiency by no catalytic converters. One of the most important ways to control and reduce emissions from vehicles is to conduct periodic technical inspection (PTI). According to the regulations of each country, the frequency of periodic technical inspection is different and is determined by the quality of air. Data of light vehicles, which had been tested in 2010, was collected from Tehran vehicle technical inspection bureau. Collected information of data on vehicles manufactured from 2004 to 2008 including Pride, Peugeot 206, Peugeot 405, Peugeot Pars, Samand and Roa. About 248865 and 236084 vehicles were studied for HC and CO emissions, respectively. According to results one vehicle among every 6 Roa, every 14 Pride, every 22 Peugeot 405, every 40 Peugeot 206, every 125 Samand and every 111 Peugeot Pars, which were referred to technical inspection centers for first time, two years after manufacture, had higher pollutants emission compared to the permitted standards. The results showed that if the periodic technical inspection intervals of vehicles increase from two years to more than two years, for example to five years, about 17.5 % of Peugeot 405 and 10.8 % of pride will be recorded for CO emissions higher than standard rate. Also, about 62 % of new vehicles will have higher levels of HC emissions, which can cause air pollution and an increase in the concentration of pollutants and eventually cause serious harm to public health

Context: Transient ischemic dilatation (TID) of the left ventricle is a non-invasive marker of suspected or known Coronary Artery Disease (CAD), and is used for the prediction of prognosis. Because the value of TID has been emphasized by current publications in clinical nuclear cardiology field, the current review of the literature was conducted to present comprehensive overview on the findings in this field.
Evidence Acquisition: Relevant literature was obtained by searching online databases, including MEDLINE/PubMed, Google Scholar, and Science Direct using the following keywords: transient ischemic dilation, Single Photon Emission Computed Tomography Myocardial Perfusion Imaging (SPECT MPI), procedural guidelines for myocardial perfusion imaging, and coronary artery disease. Articles were inspected to obtain good agreement criteria pertinent to the objective of the study. Overall, 21 relevant articles were selected to be included in the review.
Stress-induced subendocardial hypoperfusion, post-ischemic stunning, and impaired coronary flow reserve have been reported as common causes of TID. Transient Ischemic Dilatation can be easily measured by available automatic software on the market, including Emory Cardiac Toolbox, 4D-MSPECT, etc. A close correlation between TID and LV volume/function has been emphasized by previous researchers. Transient Ischemic Dilatation, in the setting of a cardiac SPECT MPI with abnormal findings, has been known to be a robust indicator of severe/extensive CAD and future cardiac events. However, only a limited number of publications are available for its probable use in the setting of normal MPI, especially based on patients at high-risk and those with TID.
By using an upper limit value of TID that is derived according to the optimum imaging procedure of a particular laboratory, routine reporting of TID measurement as part of conventional SPECT MPI analysis may be useful.

Delhi is the most urbanized city in India. Inventory estimates for the emissions of greenhouse gases and other pollutants like CO2, CO, NOx, and volatile organic compound from transport sector in Delhi, has been developed using bottom up approach provided by Intergovernmental panel on climate change (IPCC-1996). The impacts of policy option in transport sector like introduction of Compressed Natural Gas for public transport in Delhi and introduction of Euro-1 norms for vehicles have also been estimated. The emission inventory reveals that total emission of pollutants from different categories vehicles have increased during the period 1990-2000. For example, the CO2 emission (1000, tones) from gasoline driven vehicle (MC/SC) in Delhi has increased from 766 in 1990-91 to 1187 in 1999-00. The diesel driven vehicles Light commercial vehicles in Delhi has contributed to 577 CO2 in 1990-91, which increased to 9779 in 1999-00. For other pollutants also, which have been estimated here, an increase in total emission from gasoline and diesel driven vehicles has been observed during this 1990-2000 periods. This study shows that the over all contribution of pollutants in the total emissions from gasoline and diesel driven vehicles have increased in Delhi during this period. The present study also shows that the implementation of Euro-1 in 2000 in Delhi has resulted in the decrease of total emission of CO, HC, NOx, and volatile organic compound for all the classes of vehicle for which the revised vehicle emissions norms were implemented. However this decrease in emission has become inefficient due to increase in vehicle population.