Showing papers by "Margaret Bell published in 2008"

Classification of road traffic and roadside pollution concentrations for assessment of personal exposure

Abstract: Nowadays urban pollution exposure from road transport has become a great concern in major cities throughout the world. A modelling framework has been developed to simulate Personal Exposure Frequency Distributions (PEFDs) as a function of urban background and roadside pollutant concentrations, under different traffic conditions. In this paper, we present a technique for classifying roads, according to their traffic conditions, using the traffic characteristics and fleet compositions. The pollutant concentrations data for 2001 from 10 Roadside Pollution Monitoring (RPM) units in the city of Leicester were analysed to understand the spatial and temporal variability of the pollutant concentrations patterns. It was found that variability of pollutants during the day can be associated with specific road traffic conditions. Statistical analysis of two urban and two rural Automated Urban and Rural Network (AURN) background sites for particulates suggests that PM"2"."5 and PM"1"0 are closely related at urban sites but not at rural sites. The ratio of the two pollutants observed at Marylebone was found to be 0.748, which was applied to Leicester PM"1"0 data to obtain PM"2"."5 profiles. These results are being used as an element in the PEFDs model to estimate the impact of urban traffic on exposure.

An environmental sensor system for pervasively monitoring road networks

Abstract: This paper describes the on-going research at Newcastle University in the MESSAGE project which is a major environmental monitoring project funded jointly by the EPSRC and DfT. The MESSAGE project investigates the use of low cost wireless sensors and their deployment to create a dense, pervasive, ad-hoc network for monitoring traffic pollution in a road environment. Each of the wireless devices carries one or more sensor payloads which will capture one or more of the pollutants directly associated with road vehicle emissions. This paper will provide an overview of the deployment of a MOTES network in Gateshead, UK, to measure a variety of pollutants and also explore whether other pervasive sensors, such as vehicle detectors can be included in the overall monitoring package. The research will cover three distinct areas: the network development; the applications developed for monitoring pollutants; and an investigation as to how the data collected could be used to validate and calibrate emissions and dispersions models. A final step will be to explore how this vast array or real-time data could be used to modify and influence real traffic control schemes, to give environmental measurements a clear, policy-sensitive role in future traffic management and control schemes.

Impact of Driving Cycles on Greenhouse Gas Emissions and Fuel Economy for SI Car Real World Driving

Abstract: The transport sector is one of the major contributors to greenhouse gas emissions. This study investigated three greenhouse gases emitted from road transport: CO2, N2O and CH4 emissions as a function of engine warm up and driving cycles. Five different urban driving cycles were developed and used including free flow driving and congested driving. An in-vehicle FTIR (Fourier Transform Inferred) emission measurement system was installed on a EURO2 emission compliant SI (Spark Ignition) car for emissions measurement at a rate of 0.5 HZ under real world urban driving conditions. This emission measurement system was calibrated on a standard CVS (Constant Volume Sampling) measurement system and showed excellent agreement on CO2 measurement with CVS results. The N2O and CH4 measurement was calibrated using calibration gas in lab. A MAX710 real time in-vehicle fuel consumption measurement system was installed in the test vehicle and real time fuel consumption was then obtained. The temperatures across the TWC (Three Way Catalyst) and engine out exhaust gas lambda were measured. The GHG (greenhouse gas) mass emissions and consequent GWP (Global Warming Potential) for different urban diving conditions were analyzed and presented. The results provided a better understanding of traffic related greenhouse gas emission profile in urban area and will contribute to the control of climate change.

Chassis Dynamometer Evaluation of On-Board Exhaust Emission Measurement System Performance in SI Car under Transient Operating Conditions

Abstract: A commercial on-board exhaust emissions measurement system, the Horiba OBS-1300, was evaluated in a series of chassis dynamometer test trails. A EURO 1 (petrol) SI passenger car, operated under normal and rich combustion conditions, and a combination of static and transient sampling provided a wide range of measurement conditions for the evaluation exercise. The chassis dynamometer facility incorporated an 'industry standard' measurement system comprising MEXA-7400 gas analyzer and CVS bag sampling system which were used as 'benchmarks' for the evaluation of both OBS-1300 component (exhaust flow meter and species analyzer) measurements and 'daughter' emission measurements for regulated gas-phase species (CO, CO2, HC and NOx). Trials demonstrated very good to reasonable agreement for exhaust flow and CO, CO2 and HC concentration measurements during static (R2 ≈ 0.97, 0.99, 0.99 and 0.97, respectively) and transient (R2 ≈ 0.88, 0.96, 0.95 and 0.86, respectively) testing. Transient emission measurements of CO, CO2 and HC were generally consistent with 'parent' exhaust and species analyzer measurements (R2 ≈ 0.89, 0.89 and 0.81, respectively). Minor issues associated with exhaust flow measurement error at engine 'tick-over'/idle and HC measurement agreement under different engine operating conditions are discussed. However, in general, the OBS-1300 provided a reliable measure of CO, CO2 and HC exhaust emissions under all conditions investigated. By contrast, the OBS NOx sensor cross-sensitivity to NH3 hindered the reliability of NOx data, especially under rich engine operation conditions.

UTMC compliant database to support technologies of the future

Abstract: This paper will present the results of an in depth investigation of the standard database format defined by the Common Database project, UTMC10, funded by the Department for Transport on the mid 1990s applied to diverse datasets. It outlines the difficulties encountered in implementing the database platform to embrace different sources, (namely accident, pollutant concentrations, registration plate, journey time etc.) and to include both dynamic (vehicle tracking, tailpipe emissions, bus stop arrival times, car park occupancies etc) and static (public transport time tables, car parking charges etc.) data with different dimensions, sampling frequencies and accuracies. The paper will look at the requirements of Urban Traffic Management and Control compliant database infrastructure in the context of the delivery of wider policy objectives to those relating to traffic. In particular, to create the statistical processing capability that defines the current and changing status of the network, to provide the platform upon which to build a historic picture of the network to allow a statistical forecasting capability and to develop the foundations for model validation and evaluation. In this way the infrastructure needed to deliver policy objectives which not only embrace traffic management but also public transport, air quality, health impacts and climate change will be formulated.

An Environmental Sensor System For Road Networks: Message Project

Abstract: This paper describes the on-going research at Newcastle University in the Mobile Environmental Sensing System Across Grid Environments (MESSAGE) project, a major environmental monitoring project funded jointly by the United Kingdom Engineering and Physical Sciences Research Council (EPSRC) and the Department for Transport (DfT). The MESSAGE project investigates the use of low cost wireless sensors and their deployment to create a dense, pervasive, ad-hoc network for monitoring traffic pollution in a road environment. Each of the wireless devices carries one or more sensor payloads which will capture one or more of the pollutants directly associated with road vehicle emissions. This paper will provide an overview of the deployment of a MOTES network in Gateshead, United Kingdom, to measure a variety of pollutants and also explore whether other pervasive sensors, such as vehicle detectors can be included in the overall monitoring package. The key enabling technology to achieve these objectives is a sensor device or ‘mote’ capable of measuring multiple parameters and relaying data via wireless communications. The paper covers three distinct areas: the network development; the applications developed for monitoring pollutants; and an investigation as to how the data collected could be used to validate and calibrate emissions and dispersions models. A final step will be to explore how this vast array of real-time data could be used to modify and influence real traffic control schemes, to give environmental measurements a clear, policy-sensitive role in future traffic management and control schemes. The authors conclude that these low cost sensor packages will never provide the same level of sensing accuracy as the traditional AQM (Air Quality Monitoring) stations that local authorities currently deploy. However, one must consider how accuracy in sensing can be traded off against the breadth achieved from the deployment of hundreds of low-cost sensors, providing an area-wide real-time view of an area.