scholarly journals Spatial inter-comparison of Top-down emission inventories in European urban areas

2018 ◽  
Vol 173 ◽  
pp. 142-156 ◽  
Author(s):  
Marco Trombetti ◽  
Philippe Thunis ◽  
Bertrand Bessagnet ◽  
Alain Clappier ◽  
Florian Couvidat ◽  
...  
Keyword(s):  
Urban Areas ◽  
Emission Inventories ◽  
Top Down

scholarly journals Top-Down NOX Emissions of European Cities Based on the Downwind Plume of Modelled and Space-Borne Tropospheric NO2 Columns

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2893 ◽  
Author(s):  
Willem W. Verstraeten ◽  
Klaas Folkert Boersma ◽  
John Douros ◽  
Jason E. Williams ◽  
Henk Eskes ◽  
...  
Keyword(s):  
Urban Areas ◽  
Transport Model ◽  
Nox Emissions ◽  
Inventory Data ◽  
Ozone Monitoring Instrument ◽  
Top Down ◽  
Chemistry Transport Model ◽  
European Cities ◽  
Tropospheric No2

Top-down estimates of surface NOX emissions were derived for 23 European cities based on the downwind plume decay of tropospheric nitrogen dioxide (NO2) columns from the LOTOS-EUROS (Long Term Ozone Simulation-European Ozone Simulation) chemistry transport model (CTM) and from Ozone Monitoring Instrument (OMI) satellite retrievals, averaged for the summertime period (April–September) during 2013. Here we show that the top-down NOX emissions derived from LOTOS-EUROS for European urban areas agree well with the bottom-up NOX emissions from the MACC-III inventory data (R2 = 0.88) driving the CTM demonstrating the potential of this method. OMI top-down NOX emissions over the 23 European cities are generally lower compared with the MACC-III emissions and their correlation is slightly lower (R2 = 0.79). The uncertainty on the derived NO2 lifetimes and NOX emissions are on average ~55% for OMI and ~63% for LOTOS-EUROS data. The downwind NO2 plume method applied on both LOTOS-EUROS and OMI tropospheric NO2 columns allows to estimate NOX emissions from urban areas, demonstrating that this is a useful method for real-time updates of urban NOX emissions with reasonable accuracy.

scholarly journals Exploring Gaps between Bottom-Up and Top-Down Emission Estimates Based on Uncertainties in Multiple Emission Inventories: A Case Study on CH4 Emissions in China

2019 ◽  
Vol 11 (7) ◽  
pp. 2054 ◽  
Author(s):  
Penwadee Cheewaphongphan ◽  
Satoru Chatani ◽  
Nobuko Saigusa
Keyword(s):  
Coal Mining ◽  
Rice Cultivation ◽  
Emission Inventories ◽  
Ch4 Emission ◽  
Top Down ◽  
Activity Data ◽  
Bottom Up ◽  
Ch4 Emissions ◽  
Model Studies ◽  
Livestock Sector

Bottom-up CH4 emission inventories, which have been developed from statistical analyses of activity data and country specific emission factors (EFs), have high uncertainty in terms of the estimations, according to results from top-down inverse model studies. This study aimed to determine the causes of overestimation in CH4 bottom-up emission inventories across China by applying parameter variability uncertainty analysis to three sets of CH4 emission inventories titled PENG, GAINS, and EDGAR. The top three major sources of CH4 emissions in China during the years 1990–2010, namely, coal mining, livestock, and rice cultivation, were selected for the investigation. The results of this study confirm the concerns raised by inverse modeling results in which we found significantly higher bottom-up emissions for the rice cultivation and coal mining sectors. The largest uncertainties were detected in the rice cultivation estimates and were caused by variations in the proportions of rice cultivation ecosystems and EFs; specifically, higher rates for both parameters were used in EDGAR. The coal mining sector was associated with the second highest level of uncertainty, and this was caused by variations in mining types and EFs, for which rather consistent parameters were used in EDGAR and GAINS, but values were slightly higher than those used in PENG. Insignificant differences were detected among the three sets of inventories for the livestock sector.

scholarly journals Impact of spatial proxies on the representation of bottom-up emission inventories: A satellite-based analysis

2017 ◽  
Vol 17 (6) ◽  
pp. 4131-4145 ◽  
Author(s):  
Guannan Geng ◽  
Qiang Zhang ◽  
Randall V. Martin ◽  
Jintai Lin ◽  
Hong Huo ◽  
...  
Keyword(s):  
Population Density ◽  
Rural Areas ◽  
Urban Areas ◽  
Model Performance ◽  
Road Transport ◽  
Industrial Sector ◽  
Transport Sector ◽  
Emission Inventories ◽  
Bottom Up ◽  
The Impact

Abstract. Spatial proxies used in bottom-up emission inventories to derive the spatial distributions of emissions are usually empirical and involve additional levels of uncertainty. Although uncertainties in current emission inventories have been discussed extensively, uncertainties resulting from improper spatial proxies have rarely been evaluated. In this work, we investigate the impact of spatial proxies on the representation of gridded emissions by comparing six gridded NOx emission datasets over China developed from the same magnitude of emissions and different spatial proxies. GEOS-Chem-modeled tropospheric NO2 vertical columns simulated from different gridded emission inventories are compared with satellite-based columns. The results show that differences between modeled and satellite-based NO2 vertical columns are sensitive to the spatial proxies used in the gridded emission inventories. The total population density is less suitable for allocating NOx emissions than nighttime light data because population density tends to allocate more emissions to rural areas. Determining the exact locations of large emission sources could significantly strengthen the correlation between modeled and observed NO2 vertical columns. Using vehicle population and an updated road network for the on-road transport sector could substantially enhance urban emissions and improve the model performance. When further applying industrial gross domestic product (IGDP) values for the industrial sector, modeled NO2 vertical columns could better capture pollution hotspots in urban areas and exhibit the best performance of the six cases compared to satellite-based NO2 vertical columns (slope  =  1.01 and R2 = 0. 85). This analysis provides a framework for information from satellite observations to inform bottom-up inventory development. In the future, more effort should be devoted to the representation of spatial proxies to improve spatial patterns in bottom-up emission inventories.

scholarly journals Comparison and evaluation of anthropogenic emissions of SO<sub>2</sub> and NO<sub><i>x</i></sub> over China

2018 ◽  
Vol 18 (5) ◽  
pp. 3433-3456 ◽  
Author(s):  
Meng Li ◽  
Zbigniew Klimont ◽  
Qiang Zhang ◽  
Randall V. Martin ◽  
Bo Zheng ◽  
...  
Keyword(s):  
Power Plants ◽  
Comprehensive Evaluation ◽  
National Level ◽  
Model Performance ◽  
Chemical Transport ◽  
Emission Factors ◽  
Emission Inventories ◽  
Ozone Monitoring Instrument ◽  
Top Down ◽  
Bottom Up

Abstract. Bottom-up emission inventories provide primary understanding of sources of air pollution and essential input of chemical transport models. Focusing on SO2 and NOx, we conducted a comprehensive evaluation of two widely used anthropogenic emission inventories over China, ECLIPSE and MIX, to explore the potential sources of uncertainties and find clues to improve emission inventories. We first compared the activity rates and emission factors used in two inventories and investigated the reasons of differences and the impacts on emission estimates. We found that SO2 emission estimates are consistent between two inventories (with 1 % differences), while NOx emissions in ECLIPSE's estimates are 16 % lower than those of MIX. The FGD (flue-gas desulfurization) device penetration rate and removal efficiency, LNB (low-NOx burner) application rate and abatement efficiency in power plants, emission factors of industrial boilers and various vehicle types, and vehicle fleet need further verification. Diesel consumptions are quite uncertain in current inventories. Discrepancies at the sectorial and provincial levels are much higher than those of the national total. We then examined the impacts of different inventories on model performance by using the nested GEOS-Chem model. We finally derived top-down emissions by using the retrieved columns from the Ozone Monitoring Instrument (OMI) compared with the bottom-up estimates. High correlations were observed for SO2 between model results and OMI columns. For NOx, negative biases in bottom-up gridded emission inventories (−21 % for MIX, −39 % for ECLIPSE) were found compared to the satellite-based emissions. The emission trends from 2005 to 2010 estimated by two inventories were both consistent with satellite observations. The inventories appear to be fit for evaluation of the policies at an aggregated or national level; more work is needed in specific areas in order to improve the accuracy and robustness of outcomes at finer spatial and also technological levels. To our knowledge, this is the first work in which source comparisons detailed to technology-level parameters are made along with the remote sensing retrievals and chemical transport modeling. Through the comparison between bottom-up emission inventories and evaluation with top-down information, we identified potential directions for further improvement in inventory development.

scholarly journals Study on Increase in Stability of Floating and Underground Extension Method through Slab Pre-Construction

2021 ◽  
Vol 13 (24) ◽  
pp. 13696
Author(s):  
Uiseok Kim ◽  
Byungchan Min ◽  
Junghoon Kim ◽  
Hangseok Choi ◽  
Sangwoo Park
Keyword(s):  
Urban Areas ◽  
Construction Method ◽  
Economic Damage ◽  
Ground Settlement ◽  
Test Bed ◽  
Top Down ◽  
Extension Method ◽  
Management Standards ◽  
Vibration Problems ◽  
The Stability

The development of underground spaces in urban areas plays a crucial role in the regeneration and sustainability of cities. However, the conventional underground excavation works in metropolises limit the use of the ground facilities owing to stability, noise, and vibration problems, which may cause huge economic damage. In this study, a method of pre-constructing slabs of underground facilities was analyzed to improve the stability of the floating and underground extension method, even during the use of the target building. First, a numerical simulation was conducted to compare the stability of the top-down method with slab pre-construction with that of the conventional top-down method. Then, the stability of the test bed was checked by applying this construction method to the field. As a result, the top-down method with slab pre-construction significantly improved the stability of the target building by preventing the buckling of the columns and supporting members. The increase in the displacement of existing columns and supporting members was controlled after the pre-construction of the slab. In addition, the crack width and ground settlement were stable within the management standards at the field. Thus, this construction method is expected to be crucial in pursuing urban regeneration and sustainability through the efficient development of underground spaces.

scholarly journals Nitrogen Oxides Concentration and Emission Change Detection During COVID-19 Restrictions in North India

2020 ◽  
Author(s):  
Prakhar Misra ◽  
Masayuki Takigawa ◽  
Pradeep Khatri ◽  
Surendra Dhaka ◽  
A. Dimri ◽  
...  
Keyword(s):  
Rural Areas ◽  
Urban Areas ◽  
Power Plants ◽  
Anthropogenic Activities ◽  
Phase 1 ◽  
Substantial Reduction ◽  
North India ◽  
Nox Emissions ◽  
Top Down ◽  
Monitoring Instrument

Abstract COVID-19 induced restrictions resulted in a lowered fine aerosol particle and trace gas concentration across several urban places around the world, providing a natural opportunity to study effects of anthropogenic activities on emissions of air pollutants. Impact of sudden suspension of human activities on air pollution was analyzed by studying the change in satellite retrieved NO2 concentrations and top-down NOx emission over the urban and rural areas around Delhi. NO2 was chosen for being the most indicative of emission intensity due to its short lifetime of the order of a few hours in the planetary boundary layer. We present a robust temporal comparison of Ozone Monitoring Instrument (OMI) retrieved NO2 column density during the lockdown with the counterfactual baseline concentrations, extrapolated from the long-term trend and seasonal cycle components of NO2 using observations during 2015 to 2019. NO2 columns in the urban area of Delhi experienced an anomalous relative change ranging from 60.0% decline during the Phase 1 of lockdown (March 25-April 13, 2020) to 3.4% during the post-lockdown Phase 5. In contrast, we find no substantial reduction in NO2 concentrations over the rural areas. To clarify the quantitative impact of the lockdown measures, weekly top-down NOx emissions were estimated from TROPOspheric Monitoring Instrument (TROPOMI) retrieved NO2 by accounting for horizontal advection derived from the steady state continuity equation. NOx emissions from urban areas and power plants exhibited a mean decline of 72.19% and 53.4% respectively in Phase 1 compared to the pre-lockdown business-as-usual phase. Due to absence of confounding emission source activity during lockdown, emission estimates over urban areas and power-plants were validated with respective electricity generation reports and Google’s mobility reports. A higher anomaly in emission estimates suggests that comparison of only concentration change, without accounting for the dynamical and photochemical conditions, may mislead evaluation of lockdown impact. Our results are also useful for optimizing bottom-up emission inventories.

Community-led governance: Opportunities and constraints

2020 ◽  
pp. 123-146
Author(s):  
John Sturzaker ◽  
Alexander Nurse
Keyword(s):  
Empirical Data ◽  
Urban Areas ◽  
Urban Governance ◽  
Top Down ◽  
History Of

The notion, and practice, of devolving power to communities is now widespread, and since 2010 has been a particularly important element of the reforms to urban governance instituted by successive UK Governments. There has been a great deal of entirely justifiable scepticism about this, but recent evidence suggests that there may be scope for some of the reforms, specifically new “Neighbourhood Plans”, to play a progressive and emancipatory role in cities. This chapter reviews the contested history of governance at the community scale, considering both the formal devolution of power and more radical community-led approaches. It contrasts a predominantly top-down approach in England with seemingly more genuine attempts at devolution elsewhere, and introduces empirical data on Neighbourhood Plans in urban areas.

scholarly journals Spatial and temporal variation of historical anthropogenic NMVOCs emission inventories in China

2008 ◽  
Vol 8 (23) ◽  
pp. 7297-7316 ◽  
Author(s):  
Y. Bo ◽  
H. Cai ◽  
S. D. Xie
Keyword(s):  
Emission Intensity ◽  
Urban Areas ◽  
Annual Variation ◽  
Average Rate ◽  
Central China ◽  
Spatial And Temporal Variation ◽  
Emission Inventories ◽  
Growth Trend ◽  
Continuous Growth ◽  
Open Burning

Abstract. Multiyear emission inventories of anthropogenic NMVOCs in China for 1980–2005 were established based on time-varying statistical data, literature surveyed and model calculated emission factors, which were further gridded at a high spatial resolution of 40 km×40 km using the GIS methodology. Results show a continuous growth trend of China's historical NMVOCs emissions during the period of 1980–2005, with the emission increasing by 4.2 times at an annual average rate of 10.6% from 3.91 Tg in 1980 to 16.49 Tg in 2005. Vehicles, biomass burning, industrial processes, fossil fuel combustion, solvent utilization, and storage and transport generated 5.50 Tg, 3.84 Tg, 2.76 Tg, 1.98 Tg, 1.87 Tg, and 0.55 Tg of NMVOCs, respectively, in 2005. Motorcycles, biofuel burning, heavy duty vans, synthetic fibre production, biomass open burning, and industrial and commercial consumption were primary emission sources. Besides, source contributions of NMVOCs emissions showed remarkable annual variation. However, emissions of these sources had been continuously increasing, which coincided well with China's economic growth. Spatial distribution of NMVOCs emissions illustrates that high emissions mainly concentrates in developed regions of northern, eastern and southern coastal areas, which produced more emissions than the relatively underdeveloped western and inland regions. Particularly, southeastern, northern, and central China covering 35.2% of China's territory, generated 59.4% of the total emissions, while the populous capital cities covering merely 4.5% of China's territory, accounted for 24.9% of the national emissions. Annual variation of regional emission intensity shows that emissions concentrating in urban areas tended to transfer to rural areas year by year. Moreover, eastern, southern, central, and northeastern China were typical areas of high emission intensity and had a tendency of expanding to the northwestern China, which revealed the transfer of emission-intensive plants to these areas, together with the increase of biomass open burning.

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