خيارات البحث
النتائج 1 - 5 من 5
Emission and Environmental Goals in Decision Making Modeling for Load Dispatch
2020
Karim, M. H. | Memarian, H. | Valitabar, Y.
The main purpose of this research is to determine the generation quantity of each generator in a power system. In this way, not only will the electricity demanded by the system be supplied, but the cost of fuel along with the level of pollution can be minimized. Obviously, calculation of the optimal layout of power plants with the aim of minimizing fuel costs and pollutants level contributes to sustainable socio-economic development. For this purpose, modeling a multi-objective decision making framework by means of the weighting method makes it possible to attain the mentioned goals. After modeling the goals and constraints of the power system, the problem associated with economic-environmental load dispatch with the Institute of Electrical and Electronics Engineers 30-Bus data is optimized by means of the Lagrange approach. Moreover, the sensitivity analysis in connection with the weight of short-term costs is conducted to determine the final point of the system usage. Results show that if the importance coefficient of the fuel cost reduction is 1 (W=1), the economic and environmental load dispatch will pose some problems for the economic load dispatch. In contrast, if the importance coefficient of the reducing fuel cost is zero (W=0), the economic and environmental load dispatch will become problematic for environmental load dispatch. Incidentally, the trade off curve of the fuel cost and the pollutant amount involves the functional information for the system operator. The current research is mainly innovative in its use of a method to reduce fuel consumption and environmental impacts on emission at optimization process. This can, in turn, lead to generation of sustainable energy.
اظهر المزيد [+] اقل [-]Effect of northern boreal forest fires on PAH fluctuations across the arctic
2020
Luo, Jinmu | Han, Yunman | Zhao, Yuan | Huang, Yufei | Liu, Xinrui | Tao, Shu | Liu, Junfeng | Huang, Tao | Wang, Linfei | Chen, Kaijie | Ma, Jianmin
Polycyclic aromatic hydrocarbons (PAHs) are formed by the incomplete combustion of fossil fuels and forest or biomass burning. PAHs undergo long-range atmospheric transport, as evidenced by in situ observations across the Arctic. However, monitored atmospheric concentrations of PAHs indicate that ambient PAH levels in the Arctic do not follow the declining trend of worldwide anthropogenic PAH emissions since the 2000s, suggesting missing sources of PAHs in the Arctic or other places across the Northern Hemisphere. To trace origins and causes for the increasing trend of PAHs in the Arctic, the present study reconstructed PAH emissions from forest fires in the northern boreal forest derived by combining forest carbon stocks and MODIS burned area. We examined the statistical relationships of forest biomass, MODIS burned area, emission factors, and combustion efficiency with different PAH congeners. These relationships were then employed to construct PAH emission inventories from forest biomass burning. We show that for some PAH congeners, for example, benzo[a]pyrene (BaP)—the forest-fire-induced air emissions are almost one order of magnitude higher than previous emission inventories in the Arctic. A global-scale atmospheric chemistry model, GEOS-Chem, was used to simulate air concentrations of BaP, a representative PAH congener primarily emitted from biomass burning, and to quantify the response of BaP to wildfires in the northern boreal forest. The results showed that BaP emissions from wildfires across the northern boreal forest region played a significant role in the contamination and interannual fluctuations of BaP in Arctic air. A source-tagging technique was applied in tracking the origins of BaP pollution from different northern boreal forest regions. We also show that the response of BaP pollution at different Arctic monitoring sites depends on the intensity of human activities.
اظهر المزيد [+] اقل [-]Emission estimation and fate modelling of three typical pesticides in Dongjiang River basin, China
2020
Zhang, Bing | Zhang, Qian-Qian | Zhang, Shao-Xuan | Xing, Cheng | Ying, Guang-Guo
Pesticides are widely and intensively used in the world for crops protection. High pesticide loadings can potentially pollute the water resource. However, little is known about the usage, environmental emission and fate of pesticides in river basins. Here, we firstly established a pesticide emission estimation method, and investigated the environmental fate of three commonly used pesticides (chlorpyrifos, triazophos, and isoprothiolane) in Dongjiang River basin, southern China using mathematical modelling approach in combination with field monitoring. The distributed hydrological model SWAT (Soil and Water Assessment Tool) was applied to model the emission of the target pesticides from farmland to stream water, and their fate in the basin. A satisfactory model calibration for flow and suspended sediment was obtained based on eight-year observation data of four hydrological monitoring stations in Dongjiang River basin. The differences between the simulation and observation of pesticides were almost within an order of magnitude, including more than 53% differences within 0.5 order of magnitude. In the river basin, 78860 kg of chlorpyrifos, 54990 kg of triazophos and 35320 kg of isoprothiolane were sprayed onto the crops, the estimated annual emissions of the basin come up to 1801 kg, 3779 kg, and 2330 kg under the conditions of rainfall, surface runoff and percolation. After a series of environmental processes including settlement and degradation within the channels, the predicted export masses for chlorpyrifos, triazophos and isoprothiolane were reduced to 266 kg, 1858 kg, 1350 kg, respectively. Successful prediction suggests that the reliable estimation method combing the SWAT modelling can help us understand the source, concentration levels and fate of pesticides in river basin in different scales. Combing the method of emission and fate modelling method we proposed, countries and regions lacking pesticide-application database can facilitate better management of pesticides.
اظهر المزيد [+] اقل [-]Trends of production, consumption and environmental emissions of Decabromodiphenyl ether in mainland China
2020
Chen, Yuan | Li, Jinhui | Tan, Quanyin
Decabromodiphenyl ether (DecaBDE) is a brominated flame retardant belonging to the group of polybrominated diphenyl ethers. DecaBDE has been widely used for various applications, such as plastics, textiles, and building and construction materials. Limited information on DecaBDE production and usage inventory has been elaborated, however. Therefore, this work aimed to produce a preliminary emissions inventory of DecaBDE in mainland China by estimating production and consumption amounts of DecaBDE, and characterizing its emission factors during production and usage, based on industrial investigation and theoretical prediction. It was indicated that the total production of DecaBDE reached 464.68 thousand metric tons (kt), of which 62.72 kt were exported, since the beginning of its production. Shandong and Jiangsu provinces dominate the production, with proportions of 77.95% and 18.45%, respectively. The production stage releases most of the DecaBDE to the atmosphere, with an emissions factor of 23 ± 1.9 kg/t, followed by 20 ± 0.9 kg/t DecaBDE to waste water and 16 ± 1.0 kg/t DecaBDE as solid residue. DecaBDE emissions in the consumption stage—namely the plastic production process—are 0.17 ± 0.06–0.23 ± 0.08 kg DecaBDE to the atmosphere and 1.72 ± 0.58–2.29 ± 0.77 kg DecaBDE to solid residue, for each metric ton of plastic produced. The total annual DecaBDE emissions to waste water are 93.98–1140.9 mg—negligible. The results showed that the sources of DecaBDE environmental pollution are its manufacturing and flame-retardant plastic modification plants, which are easily overlooked by both the government and the public. Yet DecaBDE emissions elimination and the environmentally sound management of the DecaBDE waste generated from these two processes are crucial for environmental protection.
اظهر المزيد [+] اقل [-]Atmospheric remobilization of natural and anthropogenic contaminants during wildfires
2020
Isley, Cynthia Faye | Taylor, Mark Patrick
Globally, wildfires are increasing in frequency and severity, exposing populations to toxic trace elements stored within forests. Trace element and Pb isotope compositions in aerosols (n = 87) from four major wildfires near Sydney, Australia (1994-2004) were evaluated (Mood’s median test) to determine any significant differences in concentration before, during or after wildfires. The US EPA’s positive matrix factorization (PMF) model was used to distinguish a wildfire-related particulate source factor. Atmospheric concentrations of Cd and Mn were approximately 2.5 times higher during fire periods. PMF modelling distinguished a soil factor (Ca, Si, Ti and Zn) and an anthropogenically-sourced factor (Cd, Pb). The Cd, Pb anthropogenic factor was present at twice the concentration during wildfire periods (compared to before or after). Lead isotopic analyses of aerosols revealed that former leaded gasoline depositions were subject to remobilization during post-2000 wildfire periods. Trace element increases during wildfires are unlikely to exceed health-based criteria.
اظهر المزيد [+] اقل [-]