scholarly journals Evaluation of mobile emissions contributions to Mexico City's emissions inventory using on-road and cross-road emission measurements and ambient data

2009 ◽  
Vol 9 (17) ◽  
pp. 6305-6317 ◽  
Author(s):  
M. Zavala ◽  
S. C. Herndon ◽  
E. C. Wood ◽  
T. B. Onasch ◽  
W. B. Knighton ◽  
...  
Keyword(s):  
Measurement Techniques ◽  
Early Morning ◽  
Emission Factors ◽  
Top Down ◽  
Bottom Up ◽  
Emissions Inventory ◽  
Mobile Sources ◽  
Mobile Emissions ◽  
The City ◽  
Road Emission

Abstract. Mobile emissions represent a significant fraction of the total anthropogenic emissions burden in the Mexico City Metropolitan Area (MCMA) and, therefore, it is crucial to use top-down techniques informed by on-road exhaust measurements to evaluate and improve traditional bottom-up official emissions inventory (EI) for the city. We present the measurements of on-road fleet-average emission factors obtained using the Aerodyne mobile laboratory in the MCMA in March 2006 as part of the MILAGRO/MCMA-2006 field campaign. A comparison of our on-road emission measurements with those obtained in 2003 using essentially the same measurement techniques and analysis methods indicates that, in the three year span, NO emission factors remain within the measured variability ranges whereas emission factors of aldehydes and aromatics species were reduced for all sampled driving conditions. We use a top-down fuel-based approach to evaluate the mobile emissions from the gasoline fleet estimated in the bottom-up official 2006 MCMA mobile sources. Within the range of measurement uncertainties, we found probable slight overpredictions of mean EI estimates on the order of 20–28% for CO and 14–20% for NO. However, we identify a probable EI discrepancy of VOC mobile emissions between 1.4 and 1.9; although estimated benzene and toluene mobile emissions in the inventory seem to be well within the uncertainties of the corresponding emissions estimates. Aldehydes mobile emissions in the inventory, however, seem to be underpredicted by factors of 3 for HCHO and 2 for CH3CHO. Our on-road measurement-based estimate of annual emissions of organic mass from PM1 particles suggests a severe underprediction (larger than a factor of 4) of PM2.5 mobile emissions in the inventory. Analyses of ambient CO, NOx and CO/NOx concentration trends in the MCMA indicate that the early morning ambient CO/NOx ratio has decreased at a rate of about 1.9 ppm/ppm/year over the last two decades due to reductions in CO levels rather than by NOx. These trends, together with the analysis of fuel sales and fleet size, suggest that the relative contribution of diesel vehicles to overall NOx levels has increased over time in the city. Despite the impressive increase in the size of the vehicle fleet between 2000 and 2006, the early morning ambient concentrations of CO and NOx have not increased accordingly, probably due to the reported low removal rates of older vehicles, which do not have emissions control technologies, and partially due to the much lower emissions from newer gasoline vehicles. This indicates that an emission-based air quality improvement strategy targeting large reductions of emissions from mobile sources should be directed towards a significant increase of the removal rate of older, highly-polluting, vehicles.

scholarly journals Evaluation of mobile emissions contributions to Mexico City's emissions inventory using on-road and cross-road emission measurements and ambient data

2009 ◽  
Vol 9 (2) ◽  
pp. 6363-6395 ◽  
Author(s):  
M. Zavala ◽  
S. C. Herndon ◽  
E. C. Wood ◽  
T. B. Onasch ◽  
W. B. Knighton ◽  
...  
Keyword(s):  
Early Morning ◽  
Emission Factors ◽  
Top Down ◽  
Bottom Up ◽  
Emissions Inventory ◽  
Mobile Sources ◽  
Mobile Emissions ◽  
Concentration Changes ◽  
The City ◽  
Road Emission

Abstract. Mobile emissions represent a significant fraction of the total anthropogenic emissions burden in the Mexico City Metropolitan Area (MCMA) and, therefore, it is crucial to use top-down techniques informed by on-road exhaust measurements to evaluate and improve traditional bottom-up official emissions inventory (EI) for the city. We present the measurements of on-road fleet-average emission factors obtained using the Aerodyne mobile laboratory in the MCMA in March 2006 as part of the MILAGRO/MCMA-2006 field campaign. A comparison of our on-road emission measurements with those obtained in 2003 using essentially the same measurement techniques and analysis methods indicates that, in the three year span, NO emission factors remain within the measured variability ranges whereas emission factors of aldehydes and aromatics species were reduced for all sampled driving conditions. We use a top-down fuel-based approach to evaluate the mobile emissions from the gasoline fleet estimated in the bottom-up official 2006 MCMA mobile sources. Within the range of measurement uncertainties, we found probable slight overpredictions of mean EI estimates on the order of 20–28% for CO and 14–20% for NO. However, we identify a probable EI underprediction of VOC mobile emissions between 1.4 and 1.9; although estimated benzene and toluene mobile emissions in the inventory seem to be well within the uncertainties of the corresponding emissions estimates. Aldehydes mobile emissions in the inventory, however, seem to be under predicted by factors of 3 for HCHO and 2 for CH3CHO. Our on-road measurement based estimate of annual emissions of organic mass from PM1 particles suggests a severe underprediction (larger than a factor of 4) of PM2.5 mobile emissions in the inventory. Analyses of ambient CO, NOx and CO/NOx concentration trends in the MCMA indicate that the early morning ambient CO/NOx ratio has decreased at a rate of about 1.9 ppm/ppm/year over the last two decades and that the decrease has been driven by reductions in CO levels rather than by NOx concentration changes, suggesting that the relative contribution of diesel vehicles to overall NOx levels has increased over time in the city. Despite the impressive increases in the size of the vehicle fleet between 2000 and 2006, the early morning ambient concentrations of CO and NOx have not increased accordingly, probably due to the reported low removal rates of older vehicles, which do not have emissions control technologies, and partially due to the much lower emissions from newer gasoline vehicles. This indicates that an emission-based air quality control strategy targeting large reductions of emissions from mobile sources should be directed towards a significant increase of the removal rate of older, highly-polluting, vehicles.

scholarly journals REMI model: Bottom-up emissions inventories for cities with lack of data

2017 ◽  
pp. 277-288
Author(s):  
Sergio Ibarra-Espinosa ◽  
Rita Ynoue
Keyword(s):  
Emission Factors ◽  
Traffic Information ◽  
Common Denominator ◽  
South American ◽  
Engine Emissions ◽  
Bottom Up ◽  
Emissions Inventory ◽  
Mobile Sources ◽  
Emissions Inventories ◽  
American Cities

Abstract Emissions inventorying is a complex task with regulatory and/or scientific environmental purposes. In South American cities, when the task is performed, the common denominator is lack of data and documentation, and vehicles are usually the main source of pollutant of emerging and consolidated megacities. Therefore, emissions inventories is becoming more important, especially for mobile sources. In this manuscript we present the model REMI (R-EMssions-Inventory) for developing bottom-up emissions inventory for vehicles in cities with lack of data (Ibarra & Ynoue, 2016). The program was written in R (R CORE TEAM 2016) using several libraries. The program consists in several R scripts organized in folders with Inputs& Outputs. For traffic inputs uses counts or simulations, and also, it can be as a top-down method with statistical traffic information. REMI classifies vehicule data by fuel, size of motor, use and gross weight anually up to 50 years, according to EEA/EMEP guidelines and Copert (Ntziachristos, 2014). REMI has several options for emission factors, 1) Emission factors from Ntziachristos (2014), 2) local emission factors or 3) mixed emission factors. In the future REMI will include HBEFA emission factors. REMI also incorporates deterioration factors. Currently REMI estimate hot-engine emissions of 27 pollutants. Keywords: REMI, vehicular, emissions inventory, R, bottom-up.

scholarly journals A top-down assessment using OMI NO2 suggests an underestimate in the NOx emissions inventory in Seoul, South Korea during KORUS-AQ

2018 ◽  
Author(s):  
Daniel L. Goldberg ◽  
Pablo E. Saide ◽  
Lok N. Lamsal ◽  
Benjamin de Foy ◽  
Zifeng Lu ◽  
...  
Keyword(s):  
South Korea ◽  
Emission Rate ◽  
Model Simulation ◽  
Nox Emission ◽  
Metropolitan Region ◽  
Nox Emissions ◽  
Top Down ◽  
Bottom Up ◽  
Field Campaign ◽  
Emissions Inventory

Abstract. In this work, we investigate the NOx emissions inventory in Seoul, South Korea using a regional NASA Ozone Monitoring Instrument (OMI) NO2 product. We first develop a regional OMI NO2 product by re-calculating the air mass factors using a high-resolution (4 × 4 km2) WRF-Chem model simulation, which better captures the NO2 shape profiles in urban regions. We then apply a model-derived spatial averaging kernel to further downscale the retrieval and account for the sub-pixel variability. These two modifications yield OMI NO2 values in the regional product that are 1.37 larger in the Seoul metropolitan region and > 2 times larger near large industrial sources. These two modifications also yield an OMI NO2 product that is in better agreement with the Pandora NO2 spectrometer measurements acquired during the Korea U.S.-Air Quality (KORUS-AQ) field campaign. NOx emissions are then derived for the Seoul metropolitan area during the KORUS-AQ field campaign using a top-down approach with the standard and regional NASA OMI NO2 products. We first apply the top-down approach to a model simulation to ensure that the method is appropriate: the WRF-Chem simulation utilizing the bottom-up emission inventory yields a NOx emission rate of 227 ± 94 kton/yr, while the bottom-up inventory itself yields a NOx emission rate of 198 kton/yr. Using the top-down approach on the regional OM NO2 product, we derive the NOx emissions rate from Seoul to be 484 ± 201 kton/yr, and a 353 ± 146 kton/yr NOx emissions rate using the standard NASA OMI NO2 product. This suggests an underestimate of 53 % and 36 % using the regional and standard NASA OMI NO2 products respectively. To supplement this finding, we compare the NO2 simulated by WRF-Chem to observations of the same quantity acquired by aircraft and find a model underestimate. When NOx emissions in the WRF-Chem model are doubled, there is better agreement with KORUS-AQ aircraft observations. Although the current work is focused on South Korea using OMI, the methodology developed in this work can be applied to other world regions using TROPOMI and future satellite datasets (e.g., GEMS and TEMPO) to produce high-quality region-specific top-down NOx emission estimates.

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 Mapping the city scale anthropogenic heat emissions from buildings in Kuala Lumpur through a top-down and a bottom-up approach

2021 ◽  
pp. 103443
Author(s):  
Kai Wang ◽  
Yasemin D. Aktas ◽  
Liora Malki-Epshtein ◽  
Di Wu ◽  
Muhammad Firdaus Ammar Bin Abdullah
Keyword(s):  
Anthropogenic Heat ◽  
Kuala Lumpur ◽  
Top Down ◽  
Bottom Up ◽  
The City

scholarly journals Pelokalan Hak Asasi Manusia Melalui Partisipasi Publik dalam Kebijakan Berbasis Hak Asasi Manusia

Jurnal HAM ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 85
Author(s):  
Sabrina Nadilla
Keyword(s):  
Human Rights ◽  
Top Down ◽  
Bottom Up ◽  
Human Rights Based Approach ◽  
The City

Upaya untuk membawa nilai-nilai Hak Asasi Manusia (HAM) ke tingkat lokal sudah mencuat sejak 1990-an, melalui berbagai konsep, salah satunya human rights in the city. Konsep tersebut menantang pendekatan HAM yang selama ini hanya terpusat pada negara, sehingga membuka ruang bagi ide bahwa implementasi nilai-nilai HAM harus ditangani oleh berbagai tingkatan pemerintahan, bukan lagi terbatas pada pemerintah pusat. Dalam konteks Indonesia, upaya melokalkan nilai-nilai HAM telah dilakukan melalui berbagai kebijakan hak asasi manusia. Kebijakan tersebut antara lain penghargaan kabupaten/kota peduli HAM yang diselenggarakan oleh Kementerian Hukum dan Hak Asasi Manusia, dan proyek Kota HAM Bandung. Kajian ini menggunakan pendekatan kualitatif yang berbasis pada studi kasus, analisis dilakukan dengan menerapkan konsep pendekatan hak asasi manusia (human rights-based approach) dalam kebijakan hak asasi manusia. Dalam perspektif pelokalan hak asasi manusia, kebijakan HAM di Kota Bandung menunjukkan beberapa indikasi. Pertama, kebijakan Deklarasi HAM Bandung sebagai suatu kebijakan berbasis hak asasi manusia yang bersifat bottom-up masih belum mampu mendukung upaya pelokalan HAM di kota Bandung. Kedua, kebijakan Penghargaan Kabupaten/Kota Peduli HAM sebagai suatu kebijakan yang bersifat top-down, meskipun mendapatkan respons positif dari pemerintah kota dan instansi vertikal sebagai bagian dari pelaksana kebijakan, tidak mendapatkan legitimasi yang cukup dari masyarakat kota Bandung. 

scholarly journals A review on top-down and bottom-up approach for air pollution studies

2018 ◽  
Vol 7 (2) ◽  
pp. 52-60
Author(s):  
Francis Olawale Abulude ◽  
Moez Bahloul ◽  
Smart Olubayode ◽  
Ebenezer Alaba Adeoya
Keyword(s):  
Air Pollution ◽  
Source Apportionment ◽  
Pollution Control ◽  
Dispersion Modelling ◽  
Top Down ◽  
Bottom Up ◽  
Emissions Inventory ◽  
Global Problem ◽  
Sources Of Pollution

AbstractIt is a well-known fa ct that pollution is a global problem and mus t be holis ticall y ta ckled. In doing this, a dequa te knowledge of the sources of pollution is i mporta nt; therefore, the ai m of this paper is to review source a pportionment wi th reference to top-down and bottom-up methods . In this paper, dispersion modelling, emissions inventory and sa mpling methods are dis cussed. Also, anal yti cal methods invol ved in top -down source apportionment a re mentioned. The two techniques are needed to evalua te pollutants and their sources . Based on these two approa ches , pollution control s tra tegy is developed and decisions can be made on deci ding the ri ght approach to sol ve or reduce the pollution problems .

scholarly journals Exploiting satellite measurements to reduce uncertainties in UK bottom-up NO<sub>x</sub> emission estimates

2021 ◽  
Author(s):  
Richard J. Pope ◽  
Rebecca Kelly ◽  
Eloise A. Marais ◽  
Ailish M. Graham ◽  
Chris Wilson ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Spatiotemporal Variability ◽  
Nox Emissions ◽  
Ozone Monitoring Instrument ◽  
Top Down ◽  
Bottom Up ◽  
Emissions Inventory ◽  
Monitoring Instrument ◽  
Hazardous Pollutants ◽  
The Uk

Abstract. Nitrogen oxides (NOx, NO+NO2) are potent air pollutants which directly impact on human health and which aid the formation of other hazardous pollutants such as ozone (O3) and particulate matter. In this study, we use satellite tropospheric column nitrogen dioxide (TCNO2) data to evaluate the spatiotemporal variability and magnitude of the United Kingdom (UK) bottom-up National Atmospheric Emissions Inventory (NAEI) NOx emissions. Although emissions and TCNO2 represent different quantities, for UK city sources we find a spatial correlation of ~0.5 between the NAEI NOx emissions and TCNO2 from the high-spatial-resolution TROPOspheric Monitoring Instrument (TROPOMI), suggesting a good spatial distribution of emission sources in the inventory. Between 2005 and 2015, the NAEI total UK NOx emissions and long-term TCNO2 record from the Ozone Monitoring Instrument (OMI), averaged over England, show decreasing trends of 4.4 % and 2.2 %, respectively. Top-down NOx emissions were derived in this study by applying a simple mass balance approach to TROPOMI observed downwind NO2 plumes from city sources. Overall, these top-down estimates were consistent with the NAEI, but for larger cities such as London and Manchester the inventory is significantly (> 25 %) less than the top-down emissions. This NAEI NOx emission underestimate is supported by comparing simulations from the GEOS-Chem atmospheric chemistry model, driven by the NAEI emissions, with satellite and surface NO2 observations over the UK. This yields substantial model negative biases, providing further evidence to demonstrate that the NAEI may be underestimating NOx emissions in London and Manchester.

scholarly journals IN OMNIBUS REGIONIBUS? THE FOURTEEN REGIONS AND THE CITY OF ROME

2020 ◽  
Vol 88 ◽  
pp. 119-150
Author(s):  
Penelope J. Goodman
Keyword(s):  
Conceptual Framework ◽  
Social Identification ◽  
Social Meaning ◽  
Top Down ◽  
Bottom Up ◽  
Fire Services ◽  
History Of ◽  
Working Practices ◽  
The Impact ◽  
The City

Scholarship on the fourteen Augustan regions of Rome has tended to focus on their political and topographical significance. As a result, evidence for their social meaning and their impact on the mindsets and practices of the city's administrators and rulers has been under-exploited. This article seeks to address this lacuna. It begins by reviewing the history of Rome's regions and asking how and where the boundaries of the Augustan regions were recorded, before moving on to consider the impact of the regions on the Romans’ understanding and experiences of their city. This includes examining the evidence for bottom-up social identification with the regions, despite their top-down original creation. The paper also looks at the administrators who worked with the regions (regional magistrates and the food, water and fire services), arguing that the conceptual framework which the regions provided began to shape their working practices. Finally, it demonstrates the existence of a rhetoric of consistent provision across all fourteen regions, propagated especially by the emperors. The findings across all of these areas reveal that it is essential to take the regions and their impact into account when attempting to understand the topography of the city and the lives of its inhabitants.

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