scholarly journals Sources and transport of Δ<sup>14</sup>C on CO<sub>2</sub> within the Mexico City Basin and vicinity

2009 ◽  
Vol 9 (2) ◽  
pp. 7213-7237 ◽  
Author(s):  
S. A. Vay ◽  
S. C. Tyler ◽  
Y. Choi ◽  
D. R. Blake ◽  
N. J. Blake ◽  
...  
Keyword(s):  
Mexico City ◽  
Biomass Burning ◽  
North American ◽  
Nuclear Power ◽  
Fossil Fuel ◽  
Co2 Flux ◽  
Waste Incineration ◽  
Background Value ◽  
The North ◽  
Fossil Fuel Emissions

Abstract. Radiocarbon samples taken over Mexico City and the surrounding region during the MILAGRO field campaign in March 2006 exhibited an unexpected distribution: (1) relatively few samples (23%) were below the North American free tropospheric background value (57‰) despite the fossil fuel emissions from one of the world's most highly polluted environments; and (2) frequent enrichment well above the background value was observed. Correlate source tracer species and air transport characteristics were examined to elucidate influences on the radiocarbon distribution. Our analysis suggests that a combination of radiocarbon sources biased the "regional radiocarbon background" above the North American value thereby decreasing the apparent fossil fuel signature. These sources included the release of bomb or "hot" radiocarbon sequestered in plant carbon pools via the ubiquitous biomass burning in the region as well as the direct release of radiocarbon as CO2. Plausible large local perturbations include the burning of hazardous waste in cement kilns; medical waste incineration; and emissions from the Laguna Verde Nuclear Power Plant. These observations provide insight into the use of Δ14CO2 to constrain fossil fuel emissions in the megacity environment, indicating that underestimation of the fossil fuel contribution to the CO2 flux is likely wherever biomass burning coexists with urban emissions. Our findings increase the complexity required to quantify fossil fuel-derived CO2 in source-rich environments characteristic of megacities, and have implications for the use of Δ14CO2 observations in evaluating bottoms-up emission inventories and their reliability as a tool for validating national emission claims of CO2 within the framework of the Kyoto Protocol.

scholarly journals Sources and transport of Δ<sup>14</sup>C in CO<sub>2</sub> within the Mexico City Basin and vicinity

2009 ◽  
Vol 9 (14) ◽  
pp. 4973-4985 ◽  
Author(s):  
S. A. Vay ◽  
S. C. Tyler ◽  
Y. Choi ◽  
D. R. Blake ◽  
N. J. Blake ◽  
...  
Keyword(s):  
Mexico City ◽  
Biomass Burning ◽  
North American ◽  
Nuclear Power ◽  
Fossil Fuel ◽  
Co2 Flux ◽  
Background Value ◽  
The North ◽  
Local Point ◽  
Fossil Fuel Emissions

Abstract. Radiocarbon samples taken over Mexico City and the surrounding region during the MILAGRO field campaign in March 2006 exhibited an unexpected distribution: (1) relatively few samples (23%) were below the North American free tropospheric background value (57±2‰) despite the fossil fuel emissions from one of the world's most highly polluted environments; and (2) frequent enrichment well above the background value was observed. Correlate source tracer species and air transport characteristics were examined to elucidate influences on the radiocarbon distribution. Our analysis suggests that a combination of radiocarbon sources biased the "regional radiocarbon background" above the North American value thereby decreasing the apparent fossil fuel signature. Likely sources include the release of 14C-enhanced carbon from bomb 14C sequestered in plant carbon pools via the ubiquitous biomass burning in the region as well as the direct release of radiocarbon as CO2 from other "hot" sources. Plausible perturbations from local point "hot" sources include the burning of hazardous waste in cement kilns; medical waste incineration; and emissions from the Laguna Verde Nuclear Power Plant. These observations provide insight into the use of Δ14CO2 to constrain fossil fuel emissions in the megacity environment, indicating that underestimation of the fossil fuel contribution to the CO2 flux is likely wherever biomass burning coexists with urban emissions and is unaccounted for as a source of the elevated CO2 observed above local background. Our findings increase the complexity required to quantify fossil fuel-derived CO2 in source-rich environments characteristic of megacities, and have implications for the use of Δ14CO2 observations in evaluating bottom-up emission inventories and their reliability as a tool for validating national emission claims of CO2 within the framework of the Kyoto Protocol.

scholarly journals Carbon cycling in the North American coastal ocean: A synthesis

2018 ◽  
Author(s):  
Katja Fennel ◽  
Simone Alin ◽  
Leticia Barbero ◽  
Wiley Evans ◽  
Timotheé Bourgeois ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
North American ◽  
Inorganic Carbon ◽  
Co2 Flux ◽  
Carbon Fluxes ◽  
Coastal Ocean ◽  
Open Ocean ◽  
The Arctic ◽  
The North ◽  
Anthropogenic Carbon

Abstract. A quantification of carbon fluxes in the coastal ocean and across its boundaries, specifically the air-sea, land-to-coastal-ocean and coastal-to-open-ocean interfaces, is important for assessing the current state and projecting future trends in ocean carbon uptake and coastal ocean acidification, but is currently a missing component of global carbon budgeting. This synthesis reviews recent progress in characterizing these carbon fluxes with focus on the North American coastal ocean. Several observing networks and high-resolution regional models are now available. Recent efforts have focused primarily on quantifying net air-sea exchange of carbon dioxide (CO2). Some studies have estimated other key fluxes, such as the exchange of organic and inorganic carbon between shelves and the open ocean. Available estimates of air-sea CO2 flux, informed by more than a decade of observations, indicate that the North American margins act as a net sink for atmospheric CO2. This net uptake is driven primarily by the high-latitude regions. The estimated magnitude of the net flux is 160 ± 80 Tg C/y for the North American Exclusive Economic Zone, a number that is not well constrained. The increasing concentration of inorganic carbon in coastal and open-ocean waters leads to ocean acidification. As a result conditions favouring dissolution of calcium carbonate occur regularly in subsurface coastal waters in the Arctic, which are naturally prone to low pH, and the North Pacific, where upwelling of deep, carbon-rich waters has intensified and, in combination with the uptake of anthropogenic carbon, leads to low seawater pH and aragonite saturation states during the upwelling season. Expanded monitoring and extension of existing model capabilities are required to provide more reliable coastal carbon budgets, projections of future states of the coastal ocean, and quantification of anthropogenic carbon contributions.

scholarly journals Exploiting multi-wavelength aerosol absorption coefficients in a multi-time resolution source apportionment study to retrieve source-dependent absorption parameters

2019 ◽  
Vol 19 (17) ◽  
pp. 11235-11252 ◽  
Author(s):  
Alice Corina Forello ◽  
Vera Bernardoni ◽  
Giulia Calzolai ◽  
Franco Lucarelli ◽  
Dario Massabò ◽  
...  
Keyword(s):  
Source Apportionment ◽  
Biomass Burning ◽  
Time Resolution ◽  
Fossil Fuel ◽  
Traditional Approach ◽  
Optical Data ◽  
Optical Parameters ◽  
Bootstrap Analysis ◽  
Aerosol Absorption ◽  
Fossil Fuel Emissions

Abstract. In this paper, a new methodology coupling aerosol optical and chemical parameters in the same source apportionment study is reported. In addition to results on source contributions, this approach provides information such as estimates for the atmospheric absorption Ångström exponent (α) of the sources and mass absorption cross sections (MACs) for fossil fuel emissions at different wavelengths. A multi-time resolution source apportionment study using the Multilinear Engine (ME-2) was performed on a PM10 dataset with different time resolutions (24, 12, and 1 h) collected during two different seasons in Milan (Italy) in 2016. Samples were optically analysed by an in-house polar photometer to retrieve the aerosol absorption coefficient bap (in Mm−1) at four wavelengths (λ=405, 532, 635, and 780 nm) and were chemically characterized for elements, ions, levoglucosan, and carbonaceous components. The dataset joining chemically speciated and optical data was the input for the multi-time resolution receptor model; this approach was proven to strengthen the identification of sources, thus being particularly useful when important chemical markers (e.g. levoglucosan, elemental carbon) are not available. The final solution consisted of eight factors (nitrate, sulfate, resuspended dust, biomass burning, construction works, traffic, industry, aged sea salt); the implemented constraints led to a better physical description of factors and the bootstrap analysis supported the goodness of the solution. As for bap apportionment, consistent with what was expected, biomass burning and traffic were the main contributors to aerosol absorption in the atmosphere. A relevant feature of the approach proposed in this work is the possibility of retrieving a lot of other information about optical parameters; for example, in contrast to the more traditional approach used by optical source apportionment models, here we obtained source-dependent α values without any a priori assumption (α biomass burning =1.83 and α fossil fuels =0.80). In addition, the MACs estimated for fossil fuel emissions were consistent with literature values. It is worth noting that the approach presented here can also be applied using more common receptor models (e.g. EPA PMF instead of multi-time resolution ME-2) if the dataset comprises variables with the same time resolution as well as optical data retrieved by widespread instrumentation (e.g. an Aethalometer instead of in-house instrumentation).

Canada's Project Lazarus: Resurrecting US Nuclear Power?

1986 ◽  
Vol 4 (2-3) ◽  
pp. 201-206
Author(s):  
Carl E. Bagge
Keyword(s):  
United States ◽  
North American ◽  
Nuclear Power ◽  
Real Option ◽  
The United States ◽  
Coal Industry ◽  
The North ◽  
Electricity Use ◽  
Coal Market ◽  
Coal Power

The North American coal market is healthy. It will grow in the United States because electricity use will grow; and coal is America's only real option. The Canadian coal industry will grow as well. The only competition for coal in the United States is the non-coal power of Canada. We will compete and establish a natural economic frontier along our border in the east.

scholarly journals Global combustion: the connection between fossil fuel and biomass burning emissions (1997–2010)

2016 ◽  
Vol 371 (1696) ◽  
pp. 20150177 ◽  
Author(s):  
Jennifer K. Balch ◽  
R. Chelsea Nagy ◽  
Sally Archibald ◽  
David M. J. S. Bowman ◽  
Max A. Moritz ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Urban Areas ◽  
Fossil Fuel ◽  
Global Scale ◽  
Fossil Fuel Burning ◽  
Annual Carbon ◽  
Global Modelling ◽  
Human Use ◽  
Global Data ◽  
Fossil Fuel Emissions

Humans use combustion for heating and cooking, managing lands, and, more recently, for fuelling the industrial economy. As a shift to fossil-fuel-based energy occurs, we expect that anthropogenic biomass burning in open landscapes will decline as it becomes less fundamental to energy acquisition and livelihoods. Using global data on both fossil fuel and biomass burning emissions, we tested this relationship over a 14 year period (1997–2010). The global average annual carbon emissions from biomass burning during this time were 2.2 Pg C per year (±0.3 s.d.), approximately one-third of fossil fuel emissions over the same period (7.3 Pg C, ±0.8 s.d.). There was a significant inverse relationship between average annual fossil fuel and biomass burning emissions. Fossil fuel emissions explained 8% of the variation in biomass burning emissions at a global scale, but this varied substantially by land cover. For example, fossil fuel burning explained 31% of the variation in biomass burning in woody savannas, but was a non-significant predictor for evergreen needleleaf forests. In the land covers most dominated by human use, croplands and urban areas, fossil fuel emissions were more than 30- and 500-fold greater than biomass burning emissions. This relationship suggests that combustion practices may be shifting from open landscape burning to contained combustion for industrial purposes, and highlights the need to take into account how humans appropriate combustion in global modelling of contemporary fire. Industrialized combustion is not only an important driver of atmospheric change, but also an important driver of landscape change through companion declines in human-started fires. This article is part of the themed issue ‘The interaction of fire and mankind’.

scholarly journals International Trade and the Convergence in Youth Technological Awareness and Expectations within NAFTA: The Case of GMOs and Nuclear Power Technologies

2019 ◽  
Author(s):  
Ibrahim Niankara ◽  
Lee C. Adkins
Keyword(s):  
International Trade ◽  
Free Trade ◽  
North American ◽  
Nuclear Power ◽  
Genetically Modified Organisms ◽  
Situational Factors ◽  
Model Parameters ◽  
Probit Regression ◽  
The North ◽  
The Usa

Relying on the USA, Canada and Mexico extract from the cross-national data sample on the environmental affection and cognition of adolescent students (Niankara, 2019), along with seemingly unrelated bivariate weighted ordered probit regression modeling (Niankara and Zoungrana, 2018), this study reports on the convergence of technological awareness and expectations within the context of international trade. We achieve this by adopting a regional perspective in investigating the effects of affective, cognitive and situational factors on youth's awareness and expectations about genetically modified organisms (GMOs) and nuclear power technology (NPT) within the North American free trade block. Identification of model parameters is achieved using maximum simulated likelihood methods. The findings show that although it has been over 20 years as of 2015 that USA, Canada, and Mexico ratified the north American free trade agreement (NAFTA), the diffusion of technology and information within the trade block has not succeeded in homogenizing awareness and expectations about GMOs and Nuclear power technology, as observed in the youth population across the three countries. Indeed, with regards to technological awareness, compared to youth from the USA, those from Canada show 15% (GMOs) and 7.1% (NPT) more awareness respectively; while those in Mexico are respectively 34.4% and 19.5% less aware about GMOs and NPT. With respect to technological expectations, compared to youth from the USA, those from Canada and Mexico are respectively 34.4% and 39.9% more optimistic about GMOs, while 15% and 49.7% more optimistic about NPT. Overall, youth within NAFTA country members are respectively 2.5% and 6.7% more optimistic about GMOs and NPT for every level increase in their awareness about the two technologies.

scholarly journals Continental-scale enrichment of atmospheric <sup>14</sup>CO<sub>2</sub> from the nuclear power industry: potential impact on the estimation of fossil fuel-derived CO<sub>2</sub>

2011 ◽  
Vol 11 (5) ◽  
pp. 14583-14605 ◽  
Author(s):  
H. D. Graven ◽  
N. Gruber
Keyword(s):  
Nuclear Power ◽  
Fossil Fuel ◽  
Reference Station ◽  
Spent Fuel ◽  
Continental Scale ◽  
Nuclear Site ◽  
Spent Fuel Reprocessing ◽  
Potential Impact ◽  
And Inversion ◽  
Fossil Fuel Emissions

Abstract. Since aged carbon in fossil fuel contains no 14C, 14C/C ratios (Δ14C) measured in atmospheric CO2 can be used to estimate CO2 added by combustion and, potentially, provide verification of fossil CO2 emissions calculated using economic inventories. Sources of 14C from nuclear power generation and spent fuel reprocessing can counteract dilution by fossil CO2. Therefore, these nuclear sources can bias observation-based estimates of fossil fuel-derived CO2 if they are not correctly accounted for or included as a source of uncertainty. We estimate annual 14C emissions from each nuclear site in the world and conduct an Eulerian transport modeling study to investigate the continental-scale, steady-state gradients of Δ14C caused by nuclear activities and fossil fuel combustion. Over Europe, North America and East Asia, nuclear enrichment may offset 0–260 % of the fossil fuel dilution in Δ14C, corresponding to potential biases of 0 to −8 ppm in the CO2 attributed to fossil fuel emissions, larger than the bias from respiration in some areas. Growth of 14C emissions increased the potential nuclear bias over 1985–2005. The magnitude of this potential bias is largely independent of the choice of reference station in the context of Eulerian transport and inversion studies, but could potentially be reduced by an appropriate choice of reference station in the context of local-scale assessments.

scholarly journals Modeled source apportionment of black carbon particles coated with a light-scattering shell

2020 ◽  
Author(s):  
Aki Virkkula
Keyword(s):  
Black Carbon ◽  
Biomass Burning ◽  
Fossil Fuel ◽  
Size Distributions ◽  
Core Size ◽  
Carbon Particles ◽  
Aerosol Mass ◽  
Measured Absorption ◽  
Absorbing Material ◽  
Fossil Fuel Emissions

Abstract. The Aethalometer model been used widely for estimating the contributions of fossil fuel emissions and biomass burning to equivalent black carbon (eBC). The calculation is based on measured absorption Ångström exponents (αabs). The interpretation αabs is ambiguous since it is well-known that it not only depends on the dominant absorber but also on the size and internal structure of the particles, core size and shell thickness. In this work the uncertainties of the Aethalometer-model-derived apparent fractions of absorption by eBC from fossil fuel and biomass burning are evaluated with a core-shell Mie model. Biomass-burning fractions (BB(%)) were calculated for pure and coated single BC particles, for lognormal unimodal and bimodal size distributions of BC cores coated with ammonium sulfate, a scattering-only material. BB(%) was very seldom 0 % even though BC was the only absorbing material in the simulations. The shape of size distribution plays an important role. Narrow size distributions result in higher αabs and BB(%) values than wide size distributions. The sensitivity of αabs and BB(%) to variations in shell volume fractions is the highest for accumulation mode particles. This is important because that is where the largest aerosol mass is. For the interpretation of absorption Ångström exponents it would be very good to measure BC size distributions and shell thicknesses together with the wavelength dependency of absorption.

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