Fant 9998 publikasjoner. Viser side 368 av 400:
2011
2019
The city of Dhaka was chosen for this assessment due to the current ongoing project Bangladesh Air Pollution Management (BAPMAN), which concentrates mostly on the capital city Dhaka. The Greenhouse Gas and Air Pollution Interactions and Synergies model (GAINS) was used to performed this top-down assessment due to the models integrated assessment approach of capturing interactions between air pollution control and economic development, as well as its focus on presenting cost effective pollution control strategies. Results from the GAINS model assessment for Dhaka shows that for 2010 the total PM2.5 emissions were 35000 tons/year, and the total PM10 emissions were 45000 tons/year. The top sectors making up the PM emissions included Industry and Residential sectors, where the specific sub-sectors were brick/cement production and residential cooking respectively; the top activities making up the emissions were 'no fuel use' and 'fuelwood direct'. GAINS estimates that the top 3 technical control measures available for PM can eliminate approximately 1/3 of the PM emissions at a cost of .65 MEuro/year. GAINS results also shows that for Dhaka in 2010 the total SO2 emissions were 34000 tons/year, dominated by the Industrial sector, made up of the sub-sectors of new power plants and industrial combustion; top activities contributing to these emissions are hard coal and natural gas. NOX emissions for Dhaka in 2010 were 30000 tons/year, dominated by the Industrial and Transport sectors, made up of the industrial combustion/power plant and light/heavy duty sub-sectors respectively; top activities contributing to these emissions include natural gas, gasoline, and medium distillates. GHG emissions for Dhaka in 2010 exceeded 23 million tons/year, dominated by the Industrial and Agricultural sectors, comprising of the industrial combustion and new power plant sub-sectors; top activities contributing to these emissions include natural gas and hard coal.
2011
2016
2015
2016
This paper presents the results of BC inversions at high northern latitudes (>50°N) for the 2013–2015 period. A sensitivity analysis was performed to select the best representative species for BC and the best a priori emission dataset. The same model ensemble was used to assess the uncertainty of the a posteriori emissions of BC due to scavenging and removal and due to the use of different a priori emission inventory. A posteriori concentrations of BC simulated over Arctic regions were compared with independent observations from flight and ship campaigns showing, in all cases, smaller bias, which in turn witnesses the success of the inversion. The annual a posteriori emissions of BC at latitudes above 50°N were estimated as 560±171ktyr−1, significantly smaller than in ECLIPSEv5 (745ktyr−1), which was used and the a priori information in the inversions of BC. The average relative uncertainty of the inversions was estimated to be 30%.
A posteriori emissions of BC in North America are driven by anthropogenic sources, while biomass burning appeared to be less significant as it is also confirmed by satellite products. In northern Europe, a posteriori emissions were estimated to be half compared to the a priori ones, with the highest releases to be in megacities and due to biomass burning in eastern Europe. The largest emissions of BC in Siberia were calculated along the transect between Yekaterinsburg and Chelyabinsk. The optimised emissions of BC were high close to the gas flaring regions in Russia and in western Canada (Alberta), where numerous power and oil and gas production industries operate. Flaring emissions in Nenets–Komi oblast (Russia) were estimated to be much lower than in the a priori emissions, while in Khanty-Mansiysk (Russia) they remained the same after the inversions of BC. Increased emissions at the borders between Russia and Mongolia are probably due to biomass burning in villages along the Trans-Siberian Railway. The maximum BC emissions in high northern latitudes (>50°N) were calculated for summer months due to biomass burning and they are controlled by seasonal variations in Europe and Asia, while North America showed a much smaller variability.
2018
2014
2015
2009
Top-down validation of global and East Asian emissions of tetrafluoromethane and hexaflurorethane. NILU F
2010
TOR: An Overview of Tropospheric Ozone Research Transport and Chemical Transformation of Pollutants in the Troposphere, 3373, vol. 1
2000
2005
2005
2007
2022
Total oxidizable precursors assay for PFAS in human serum
Per- and polyfluoroalkyl substances (PFAS) are a class of chemicals including over 4700 substances. As a limited number of PFAS is routinely analyzed in human serum, complementary analytical methods are required to characterize the overlooked fraction. A promising tool is the total oxidizable precursors (TOP) assay to look for precursors by oxidation to perfluoroalkyl acids (PFAA). The TOP assay was originally developed for large volumes of water and had to be adapted for 250 μL of human serum. Optimization of the method was performed on serum samples spiked with model precursors. Oxidative conditions similar to previous TOP assay methods were not sufficient for complete oxidation of model precursors. Prolonged heating time (24 h) and higher oxidant amount (95 mg of Na2S2O8 per 225 μL of serum) were needed for complete conversion of the model precursors and accomplishing PFAA yields of 35–100 %. As some precursors are not fully converted to PFAA, the TOP assay can only provide semi-quantitative estimates of oxidizable precursors in human serum. However, the TOP assay can be used to give indications about the identity of unknown precursors by evaluating the oxidation products, including perfluoroalkyl sulfonic acids (PFSA) and perfluoroalkyl ether carboxylic acids (PFECA). The optimized TOP assay for human serum opens the possibility for high-throughput screening of human serum for undetected PFAA precursors.
2022