scholarly journals Reconstructing urban CO₂ emissions utilising the radiocarbon composition of tree rings from the Wellington Region, New Zealand

2021 ◽  
Author(s):  
◽  
India Ansell
Keyword(s):  
Carbon Dioxide ◽  
Tree Ring ◽  
Tree Rings ◽  
Fossil Fuel ◽  
Road Traffic ◽  
Traffic Emissions ◽  
Road Traffic Emissions ◽  
Clean Air ◽  
Emissions Inventories

<p>This study demonstrates the utility of tree ring radiocarbon analysis to quantify a temporal record of recently-added fossil fuel-derived carbon dioxide (CO₂ff) in the urban atmosphere, to retrospectively measure emissions and potentially validate local emissions inventories. Currently, there is no internationally recognised method to test emissions inventories against direct atmospheric estimations of CO₂ff. With the increasing interest in emissions control legislation, independent and objective research to validate emissions reported by governments and industries is needed.  As CO₂ff emissions are completely depleted in radiocarbon (¹⁴C), an observed decrease in the ¹⁴C content of the atmosphere is mostly due to additions of CO₂ff. As trees incorporate CO₂ from the local atmosphere into annual growth rings, it was hypothesised that an urban located tree would reflect emission rates of its local surroundings. Measurements of the ¹⁴C content of cellulose were made from the annual tree rings of a Kauri tree (Agathis australis), located in the downtown area of the Wellington suburb of Lower Hutt (KNG52). This record was compared with tree rings from two Kauri at a nearby coastal site (NIK19 and NIK23) and the long-term clean air ¹⁴CO₂ record from Baring Head. The clean air Kauri trees, NIK19 and NIK23, demonstrated excellent agreement with the Baring Head atmospheric record, indicating that the trees were accurately sampling the atmosphere. The KNG52 tree, demonstrated good agreement with the clean air record in the early part of the record (with some variability), however, exhibited significantly lower Δ¹⁴CO₂ values from the 1980s onward. Calculation of the influence of the terrestrial biosphere on the ¹⁴CO₂ record showed very little impact, determining that the variability seen was due to local additions of CO₂ff.  Historic CO₂ff emissions were calculated using the Δ¹⁴CO₂ measurements from the KNG52 ¹⁴CO₂ record for the period 1972 – 2012. Biosphere correction calculations showed that the biosphere was the dominant influence on the record in the early part of the record (1972 – 1980), with fossil fuel emissions dominating the record from 1980s onward. The observations were compared qualitatively with meteorological data and urban development in the area to assess variability in CO₂ff. A minor trend towards lower wind speeds associated with higher levels of CO₂ff was identified, indicating that local meteorology may be responsible for 10% change seen in the record. The influence of local development demonstrated some possible relation but a correlation was not significant. The KNG52 CO₂ff record was compared with national-level reported liquid (road traffic) emissions from the Carbon Dioxide Information Analysis Centre (CDIAC). The observed KNG52 CO₂ff in the tree ring record appeared to increase in tandem with road traffic emissions.</p>

scholarly journals Reconstructing urban CO₂ emissions utilising the radiocarbon composition of tree rings from the Wellington Region, New Zealand

2021 ◽  
Author(s):  
◽  
India Ansell
Keyword(s):  
Carbon Dioxide ◽  
Tree Ring ◽  
Tree Rings ◽  
Fossil Fuel ◽  
Road Traffic ◽  
Traffic Emissions ◽  
Road Traffic Emissions ◽  
Clean Air ◽  
Emissions Inventories

<p>This study demonstrates the utility of tree ring radiocarbon analysis to quantify a temporal record of recently-added fossil fuel-derived carbon dioxide (CO₂ff) in the urban atmosphere, to retrospectively measure emissions and potentially validate local emissions inventories. Currently, there is no internationally recognised method to test emissions inventories against direct atmospheric estimations of CO₂ff. With the increasing interest in emissions control legislation, independent and objective research to validate emissions reported by governments and industries is needed.  As CO₂ff emissions are completely depleted in radiocarbon (¹⁴C), an observed decrease in the ¹⁴C content of the atmosphere is mostly due to additions of CO₂ff. As trees incorporate CO₂ from the local atmosphere into annual growth rings, it was hypothesised that an urban located tree would reflect emission rates of its local surroundings. Measurements of the ¹⁴C content of cellulose were made from the annual tree rings of a Kauri tree (Agathis australis), located in the downtown area of the Wellington suburb of Lower Hutt (KNG52). This record was compared with tree rings from two Kauri at a nearby coastal site (NIK19 and NIK23) and the long-term clean air ¹⁴CO₂ record from Baring Head. The clean air Kauri trees, NIK19 and NIK23, demonstrated excellent agreement with the Baring Head atmospheric record, indicating that the trees were accurately sampling the atmosphere. The KNG52 tree, demonstrated good agreement with the clean air record in the early part of the record (with some variability), however, exhibited significantly lower Δ¹⁴CO₂ values from the 1980s onward. Calculation of the influence of the terrestrial biosphere on the ¹⁴CO₂ record showed very little impact, determining that the variability seen was due to local additions of CO₂ff.  Historic CO₂ff emissions were calculated using the Δ¹⁴CO₂ measurements from the KNG52 ¹⁴CO₂ record for the period 1972 – 2012. Biosphere correction calculations showed that the biosphere was the dominant influence on the record in the early part of the record (1972 – 1980), with fossil fuel emissions dominating the record from 1980s onward. The observations were compared qualitatively with meteorological data and urban development in the area to assess variability in CO₂ff. A minor trend towards lower wind speeds associated with higher levels of CO₂ff was identified, indicating that local meteorology may be responsible for 10% change seen in the record. The influence of local development demonstrated some possible relation but a correlation was not significant. The KNG52 CO₂ff record was compared with national-level reported liquid (road traffic) emissions from the Carbon Dioxide Information Analysis Centre (CDIAC). The observed KNG52 CO₂ff in the tree ring record appeared to increase in tandem with road traffic emissions.</p>

Tracking atmospheric carbon emissions in southern Ontario, Canada using dendrochronological records

2021 ◽  
Author(s):  
Michael Pisaric ◽  
Carley Crann ◽  
Felix Vogel
Keyword(s):  
Environmental Change ◽  
Tree Ring ◽  
Tree Rings ◽  
Fossil Fuel ◽  
Cosmic Ray ◽  
Proxy Data ◽  
Southern Ontario ◽  
Clean Air ◽  
Atmospheric Sampling ◽  
Instrumental Records

&lt;p&gt;Records of environmental change are often temporally short, perhaps spanning a few decades.&amp;#160; For many environmental issues impacting the world today, we have very limited observations or data concerning those changes.&amp;#160; Therefore, we need to supplement the short observational and instrumental records of environmental change with proxy data sources.&amp;#160; Tree-ring growth records are one type of proxy data source that can be examined at annual timescales to track changes in the environment across longer periods than afforded by relatively short observations and instrumental data records.&amp;#160; Changes in the composition of some gases in the atmosphere, are one example of environmental change that can be elucidated using tree-ring records.&amp;#160; Trees utilize various forms of carbon dioxide during photosynthesis, including radiocarbon (&lt;sup&gt;14&lt;/sup&gt;C).&amp;#160; Naturally, &lt;sup&gt;14&lt;/sup&gt;C in the atmosphere varies through time due to cosmic ray flux and ocean-atmosphere dynamics.&amp;#160; The concentration of &lt;sup&gt;14&lt;/sup&gt;C also varies due to anthropogenic activities, including burning of fossil fuels, nuclear bomb testing, and the operation of nuclear power plants (NPPs).&amp;#160; Tree rings record atmospheric &lt;sup&gt;14&lt;/sup&gt;C concentration during the growing season and are an effective tool to trace &lt;sup&gt;14&lt;/sup&gt;C in the atmosphere from a variety of sources, including NPPs.&lt;/p&gt;&lt;p&gt;In Southern Ontario, Canada there are 15 operational CANDU reactors at three NPPs (Bruce (8), Darlington (1) and Pickering (6)).&amp;#160; Southern Ontario is also one of the most densely populated regions of Canada and is a major source of fossil fuel derived carbon that is depleted in &lt;sup&gt;14&lt;/sup&gt;C. Monitoring of atmospheric &lt;sup&gt;14&lt;/sup&gt;C in Ontario is conducted at the&amp;#160;Centre for Atmospheric Research Experiments, operated by Environment and Climate Change Canada (ECCC).&amp;#160; The facility is considered a clean air site, located approximately halfway between the Bruce and Darlington NPPs.&amp;#160;&lt;/p&gt;&lt;p&gt;We measured the &amp;#916;&lt;sup&gt;14&lt;/sup&gt;C in tree rings from white spruce (Picea glauca) trees sampled across a west-east geographic transect between the NPPs with the aim of better understanding how the atmospheric concentration of &lt;sup&gt;14&lt;/sup&gt;C has varied locally in this region, while also attempting to pinpoint sources of &lt;sup&gt;14&lt;/sup&gt;C emissions. Data from our clean-air sites track globally derived &lt;sup&gt;14&lt;/sup&gt;C data from the &amp;#160;Jungfraujoch clean-air atmospheric sampling site in Switzerland.&amp;#160; Tree-ring &lt;sup&gt;14&lt;/sup&gt;Cmeasurements from our most densely populated site near the city of Toronto are depleted in &lt;sup&gt;14&lt;/sup&gt;C, reflecting fossil fuel combustion. Conversely, &lt;sup&gt;14&lt;/sup&gt;C measurements at our site nearest the Pickering and Darlington NPPs are the most enriched. Our results give insight into how tree rings record &lt;sup&gt;14&lt;/sup&gt;C and how well they compare to established atmospheric sampling techniques.&amp;#160;&lt;/p&gt;

scholarly journals Quantifying road traffic emissions embedded in a multi-objective traffic assignment model

2020 ◽  
Vol 47 ◽  
pp. 648-655 ◽  
Author(s):  
Eloísa Macedo ◽  
Ricardo Tomás ◽  
Paulo Fernandes ◽  
Margarida C. Coelho ◽  
Jorge M. Bandeira
Keyword(s):  
Traffic Assignment ◽  
Road Traffic ◽  
Traffic Emissions ◽  
Multi Objective ◽  
Road Traffic Emissions ◽  
Assignment Model

scholarly journals Integrating Modes of Transport in a Dynamic Modelling Approach to Evaluate Population Exposure to Ambient NO2 and PM2.5 Pollution in Urban Areas

2020 ◽  
Vol 17 (6) ◽  
pp. 2099 ◽  
Author(s):  
Martin Otto Paul Ramacher ◽  
Matthias Karl
Keyword(s):  
Air Pollution ◽  
Population Dynamics ◽  
Urban Areas ◽  
Road Traffic ◽  
Ambient Air ◽  
Traffic Emissions ◽  
Exposure Model ◽  
Population Exposure ◽  
Road Traffic Emissions ◽  
Pollutant Concentrations

To evaluate the effectiveness of alternative policies and measures to reduce air pollution effects on urban citizen’s health, population exposure assessments are needed. Due to road traffic emissions being a major source of emissions and exposure in European cities, it is necessary to account for differentiated transport environments in population dynamics for exposure studies. In this study, we applied a modelling system to evaluate population exposure in the urban area of Hamburg in 2016. The modeling system consists of an urban-scale chemistry transport model to account for ambient air pollutant concentrations and a dynamic time-microenvironment-activity (TMA) approach, which accounts for population dynamics in different environments as well as for infiltration of outdoor to indoor air pollution. We integrated different modes of transport in the TMA approach to improve population exposure assessments in transport environments. The newly developed approach reports 12% more total exposure to NO2 and 19% more to PM2.5 compared with exposure estimates based on residential addresses. During the time people spend in different transport environments, the in-car environment contributes with 40% and 33% to the annual sum of exposure to NO2 and PM2.5, in the walking environment with 26% and 30%, in the cycling environment with 15% and 17% and other environments (buses, subway, suburban, and regional trains) with less than 10% respectively. The relative contribution of road traffic emissions to population exposure is highest in the in-car environment (57% for NO2 and 15% for PM2.5). Results for population-weighted exposure revealed exposure to PM2.5 concentrations above the WHO AQG limit value in the cycling environment. Uncertainties for the exposure contributions arising from emissions and infiltration from outdoor to indoor pollutant concentrations range from −12% to +7% for NO2 and PM2.5. The developed “dynamic transport approach” is integrated in a computationally efficient exposure model, which is generally applicable in European urban areas. The presented methodology is promoted for use in urban mobility planning, e.g., to investigate on policy-driven changes in modal split and their combined effect on emissions, population activity and population exposure.

scholarly journals Contribution of road traffic emissions to the atmospheric black carbon burden in the mid-1990s

2001 ◽  
Vol 106 (D16) ◽  
pp. 17997-18014 ◽  
Author(s):  
Ines Köhler ◽  
Martin Dameris ◽  
Ingmar Ackermann ◽  
Heinz Hass
Keyword(s):  
Black Carbon ◽  
Road Traffic ◽  
Traffic Emissions ◽  
Road Traffic Emissions

scholarly journals A CFD study on the effectiveness of trees to disperse road traffic emissions at a city scale

2015 ◽  
Vol 120 ◽  
pp. 1-14 ◽  
Author(s):  
A.P.R. Jeanjean ◽  
G. Hinchliffe ◽  
W.A. McMullan ◽  
P.S. Monks ◽  
R.J. Leigh
Keyword(s):  
Road Traffic ◽  
Traffic Emissions ◽  
Road Traffic Emissions

scholarly journals Spatially resolved flux measurements of NOx from London suggest significantly higher emissions than predicted by inventories

2016 ◽  
Vol 189 ◽  
pp. 455-472 ◽  
Author(s):  
Adam R. Vaughan ◽  
James D. Lee ◽  
Pawel K. Misztal ◽  
Stefan Metzger ◽  
Marvin D. Shaw ◽  
...  
Keyword(s):  
Real World ◽  
Road Traffic ◽  
Measurement Data ◽  
Time Of Day ◽  
Atmospheric Emissions ◽  
Emissions Inventory ◽  
Spatially Resolved ◽  
Road Traffic Emissions ◽  
Flux Measurements ◽  
Emissions Inventories

To date, direct validation of city-wide emissions inventories for air pollutants has been difficult or impossible. However, recent technological innovations now allow direct measurement of pollutant fluxes from cities, for comparison with emissions inventories, which are themselves commonly used for prediction of current and future air quality and to help guide abatement strategies. Fluxes of NOx were measured using the eddy-covariance technique from an aircraft flying at low altitude over London. The highest fluxes were observed over central London, with lower fluxes measured in suburban areas. A footprint model was used to estimate the spatial area from which the measured emissions occurred. This allowed comparison of the flux measurements to the UK's National Atmospheric Emissions Inventory (NAEI) for NOx, with scaling factors used to account for the actual time of day, day of week and month of year of the measurement. The comparison suggests significant underestimation of NOx emissions in London by the NAEI, mainly due to its under-representation of real world road traffic emissions. A comparison was also carried out with an enhanced version of the inventory using real world driving emission factors and road measurement data taken from the London Atmospheric Emissions Inventory (LAEI). The measurement to inventory agreement was substantially improved using the enhanced version, showing the importance of fully accounting for road traffic, which is the dominant NOx emission source in London. In central London there was still an underestimation by the inventory of 30–40% compared with flux measurements, suggesting significant improvements are still required in the NOx emissions inventory.

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