Investigating the traffic-related environmental impacts of hydraulic-fracturing (fracking) operations

Hydraulic fracturing (fracking) has been used extensively in the US and Canada since the 1950s and offers the potential for significant new sources of oil and gas supply. Numerous other countries around the world (including the UK, Germany, China, South Africa, Australia and Argentina) are now giving serious consideration to sanctioning the technique to provide additional security over the future supply of domestic energy. However, relatively high population densities in many countries and the potential negative environmental impacts that may be associated with fracking operations has stimulated controversy and significant public debate regarding if and where fracking should be permitted. Road traffic generated by fracking operations is one possible source of environmental impact whose significance has, until now, been largely neglected in the available literature. This paper therefore presents a scoping-level environmental assessment for individual and groups of fracking sites using a newly-created Traffic Impacts Model (TIM). The model produces estimates of the traffic-related impacts of fracking on greenhouse gas emissions, local air quality emissions, noise and road pavement wear, using a range of hypothetical fracking scenarios to quantify changes in impacts against baseline levels. Results suggest that the local impacts of a single well pad may be short duration but large magnitude. That is, whilst single digit percentile increases in emissions of CO2, NOx and PM are estimated for the period from start of construction to pad completion (potentially several months or years), excess emissions of NOx on individual days of peak activity can reach 30% over baseline. Likewise, excess noise emissions appear negligible (< 1 dBA) when normalised over the completion period, but may be considerable (+ 3.4 dBA) in particular hours, especially in night-time periods. Larger, regional scale modelling of pad development scenarios over a multi-decade time horizon give modest CO2 emissions that vary between 2.5 and 160.4 kT, dependent on the number of wells, and individual well fracking water and flowback waste requirements. The TIM model is designed to be adaptable to any geographic area where the required input data are available (such as fleet characteristics, road type and quality), and we suggest could be deployed as a tool to help reach more informed decisions regarding where and how fracking might take place taking into account the likely scale of traffic-related environmental impacts

Rolling resistance contribution to a road pavement life cycle carbon footprint analysis

Purpose Although the impact of road pavement surface condition on rolling resistance has been included in the life cycle assessment (LCA) framework of several studies in the last years, there is still a high level of uncertainty concerning the methodological assumptions and the parameters that can affect the results. In order to adopt pavement carbon footprint/LCA as a decision-making tool, it is necessary to explore the impact of the chosen methods and assumptions on the LCA results. Methods This paper provides a review of the main models describing the impact of the pavement surface properties on vehicle fuel consumption and analyses the influence of the methodological assumptions related to the rolling resistance on the LCA results. It compares the CO2 emissions, calculated with two different rolling resistance models existing in literature, and performs a sensitivity test on some specific input variables (pavement deterioration rate, traffic growth, and emission factors/fuel efficiency improvement). Results and discussion The model used to calculate the impact of the pavement surface condition on fuel consumption significantly affects the LCA results. The pavement deterioration rate influences the calculation in both models, while traffic growth and fuel efficiency improvement have a limited impact on the vehicle CO2 emissions resulting from the pavement condition contribution to rolling resistance. Conclusions and recommendations Existing models linking pavement condition to rolling resistance and hence vehicle emissions are not broadly applicable to the use phase of road pavement LCA and further research is necessary before a widely-used methodology can be defined. The methods of modelling and the methodological assumptions need to be transparent in the analysis of the impact of the pavement surface condition on fuel consumption, in order to be interpreted by decision makers and implemented in an LCA framework. This will be necessary before product category rules (PCR) for pavement LCA can be extended to include the use phase

Macrostructural Alterations of Subcortical Grey Matter in Psychogenic Erectile Dysfunction

Psychogenic erectile dysfunction (ED) has been defined as the persistent inability to attain and maintain an erection sufficient to permit sexual performance. It shows a high incidence and prevalence among men, with a significant impact on the quality of life. Few neuroimaging studies have investigated the cerebral basis of erectile dysfunctions observing the role played by prefrontal, cingulate, and parietal cortices during erotic stimulation. In spite of the well-known involvement of subcortical regions such as hypothalamus and caudate nucleus in male sexual response, and the key role of nucleus accumbens in pleasure and reward, poor attention was paid to their role in male sexual dysfunction. In this study, we determined the presence of grey matter (GM) atrophy patterns in subcortical structures such as amygdala, hippocampus, nucleus accumbens, caudate nucleus, putamen, pallidum, thalamus, and hypothalamus in patients with psychogenic ED and healthy men. After Rigiscan evaluation, urological, general medical, metabolic and hormonal, psychological and psychiatric assessment, 17 outpatients with psychogenic ED and 25 healthy controls were recruited for structural MRI session. Significant GM atrophy of nucleus accumbens was observed bilaterally in patients with respect to controls. Shape analysis showed that this atrophy was located in the left medial-anterior and posterior portion of accumbens. Left nucleus accumbens volumes in patients correlated with low erectile functioning as measured by IIEF-5 (International Index of Erectile Function). In addition, a GM atrophy of left hypothalamus was also observed. Our results suggest that atrophy of nucleus accumbens plays an important role in psychogenic erectile dysfunction. We believe that this change can influence the motivation-related component of sexual behavior. Our findings help to elucidate a neural basis of psychogenic erectile dysfunction

The ACCRA Project. Importance of accuracy in vehicle emissions estimation for urban dynamic geofencing.

Five UK cities will implement clean air zones (CAZ) to improve air quality (AQ), specifically in relation to NO2"br" and 253 UK local authorities have declared Air Quality Management Areas for NO2. Vehicles which have an"br" internal combustion engine and an electric only range can offer zero emission (ZE) operation but cities lack the"br" ability to monitor and control the vehicles. Project ACCRA will address this problem."br" The project is of 12 month duration aiming to develop and demonstrate a system that allows hybrid ICE/EV vehicles"br" to become part of a city’s urban traffic management control system; monitoring the vehicles’ location and operational"br" state, and able to control the ZE running strategy ensuring ZE through areas of poor AQ. Using a combination of"br" estimated emissions and air quality sensors the system’s decision-making engine will demonstrate the ability to"br" respond to pollution violations and modify (on-demand) the ZE strategy of the vehicle via active geo-fencing."br" In order to support the decision on the dynamic geofencing, estimation of emissions represents an important and"br" fundamental step in the process, hence this paper focuses on the comparison of instantaneous vehicle emissions"br" modelling using traditional and low-cost GPS devices. A sensitivity test between the low-cost device (recording"br" frequency, typically 0.2Hz), and the more expensive recording at 1Hz has been performed. Results show that if"br" low-cost sensors were to be deployed in place of more expensive alternatives the emissions model underestimates"br" the total CO2 and NOx emission rates by a factor of between 5% and 20% depending on the vehicle and pollutant"br" type. The source of this divergence is identified as the sampling rate of the instrument rather than the low-cost"br" instrument. Hence, the deployment of low-cost, or specifically low resolution, sensors is only a suitable alternative"br" in situations where this margin of error is acceptable rather than a general solution."br" This result will support further development of the dynamic geofencing within this project as well as will impact"br" vehicle tracking studies using methodologies other than GPS and CAN as it constrains the effective sampling rate"br" required by these methodologies to a minimum of 1Hz as well