An intelligent transport system based on traffic air pollution control

Transcription

1 An intelligent transport system based on traffic air pollution control I. Allegrini & F. Costabile Institute for Atmospheric Pollution, Italian National Research Council, Rome, Italy Abstract In the framework of the Sino-Italian Cooperation Program held by the Italian Ministry of Environmental and Territory, an Intelligent Transport System (ITS) for the city of Beijing has been planned from the Institute for Atmospheric Pollution of the Italian National Research Council. The system investigates the direct link existing between traffic emissions and measured concentrations; this study concerns the consideration and better planning of the future development of traffic management in the city of Beijing, but also in further cities. The project target is the implementation of a tool for the reduction of traffic emissions. Therefore, the ITS input is the control of Traffic Air Pollution: by identifying the distribution of pollutants distribution through an Air Quality Monitoring System, the Beijing ITS addresses in the long term the operation of the traffic flow management system by limiting the access of traffic pollution sources and better managing public transport. According to this requirement, the main operation strategies are: measurements of pollutant concentrations in ambient air; measurements of traffic emissions; the setting-up of a simplified environmental transport model able to simulate in different scenarios the mobility and calculate the relevant vehicle emissions; monitoring of traffic sources; management of public transport. This paper gives on overview of the project findings and the related study outcomes. Keywords: intelligent transport system, air quality monitoring system, air pollution, China, urban environment. 1 Introduction Many world environmental issues are nowas related to transportation systems in mega cities. Particular emphasis is placed on solving the severe traffic

2 542 Air Pollution XII congestion and air pollution problems associated with mega cities. Cities like London, Rome, Milan, and Rotterdam, in the developed countries, have already implemented advanced transportation planning and mobile source emissions control strategies. The London solution involved the creation of a congestion zone in the city centre to reduce the number of operating vehicles during work hours; the city planners are now exploring the possibility of expanding the congestion zone to achieve an improvement in air quality in addition to a reduction in roadway congestion. The Milan and Rome solution included the imposition of high parking fees to discourage the usage of private vehicles in congested areas. In an attempt to reduce residential exposure to mobile source emissions and noise, Rotterdam imposed a constant speed zone on a highway running through a neighbourhood: minimizing speed variability and choosing a speed in the range where emissions are minimized achieved a reduction in pollutant levels and noise. In cities like Mexico City, Bogotá, Santiago, Sao Paulo, Beijing, and Shanghai, in the developing countries, innovative approaches have already been applied and tested and are now in the implementation phase. Mexico City, long known as one of the most polluted of the world s mega cities, has initiated a comprehensive program to improve air quality (Mexico City Air Quality Program). Santiago has initiated a bus rapid transit system (BRT), integrated bus-metro system, improved bus technology, reversible street directions, and land-use planning structure to greatly reduce trip duration and variability. Sao Paulo has focused on the use of alternative fuels such as ethanol and achieving increased usage among all demographic groups. Bogotá has developed a BRT system that allocated prime road space to new technology buses, increasing pedestrian space and bike use, reducing travel duration, and improving air quality, while decreasing private vehicle use. In Beijing, during the upcoming Olympic Games, an additional tool is being implemented and proposed in this paper: an intelligent transport system based on traffic air pollution control is being put in operation in order to reduce pollution levels by limiting vehicle access when high levels of ambient pollution are observed. The project is intended to better understand how the improvement of fuels and transport technology, both private and public, the reduction of vehicle pollution proportion by technological, political and scientific measures and the improvement of emission performances, could be integrated with intelligent transport management system. 2 Monitoring approach In order to control traffic air pollution by managing transport system, a new monitoring approach is pursued [1]. The air quality monitoring system has to investigate the correlation existing between exposition and emissions. This relationship is described by a very complicated nonlinear function of the pollutant concentration, depending on several further parameters; the knowledge of this function is still an open problem for the scientific community and a better comprehension of this concern is necessary to be faced in future. The air quality

3 Air Pollution XII 543 monitoring network is planned to measure the maximum possible number of the following parameters: - Trend of emission Q j (x,t) in space { x, x, 2 x3} and time (t); 1 - Trend of concentration C k in space { x, x, 2 x3} and time (t); 1 - Trend of exposition E i in space { x, x, 2 x3} and time (t); 1 - Meteorological information (flow field { u, u, 2 u 3}, eddy diffusion κ )in space 1 { x, x, 2 x3} and time (t); 1 - Forcing terms (removal processes from the atmosphere, chemical reactions, etc.). In this framework, network design [2,3,4] is targeted to two focal points: - Plan the monitoring network to measure the maximum number of parameters (reference data from automatic analyzers and additional data from new technologies), detecting and isolating weak signals (coming from unconventional data) in a wide environmental noise characteristic of megacities ambient area. - Connect traffic air pollution control systems to intelligent transport systems in order to check, in a medium-long time, the environmental meaning of emission control measures (i.e. end of pipe technology - e.g. fitting particulate traps to vehicles-, the use of alternative fuels, such as LPG, methane or hydrogen) or enforcement of emissions standards (e.g. through the use of Low Emission Zones). An ongoing project for an air quality monitoring system in the city of Suzhou, in the Popular Republic of China, is then presented in order to show the effectiveness of a monitoring network designed by following the previously described approach. The Suzhou AQMS is equipped with new scientifically advanced instrumentation: automatic monitoring stations provide information on time evolution of atmospheric pollution, while the so-called saturation stations [8] provide details about the saturated spatial distribution. Therefore, the ongoing project in the megacity of Beijing is presented in order to show the potential applications of such a kind of air quality monitoring network for the management of an intelligent transport system. 3 Suzhou AQMS In 2002, in the framework of the Sino-Italian Cooperation Program for environmental protection, the Institute for atmospheric pollution of the Italian National Research Council was appointed from the Italian Ministry of the Environment and Territory as implementation agency, to develop a pilot project for the establishment of an air quality monitoring system (AQMS) in Suzhou in cooperation with the State Environmental Protection Administration (SEPA) of China and with the Municipality of Suzhou. Suzhou is a city very close to Shanghai, with 8 districts, an area of about km 2 and a population of 2.7 million people. According to SEPA requirements, the compulsory objectives are SO 2, NO 2 and PM 10. According to the Technological Regulations of City Air

4 544 Air Pollution XII Quality Daily Report, the corresponding pollutant concentration limits of air pollution indexes are stated in Table 1. Pollution Index API Table 1: SO 2 (Daily ) Air pollution indexes in Suzhou. NO 2 (Daily ) Pollutant concentration (mg/m 3 ) PM 10 (Daily ) CO (Daily ) By pursuing the capacity building and technology transfer targets of Agenda XXI, the AQMS project is supporting the municipal authorities in policymaking process to elaborate appropriate guidelines for establishing AQMSs. Following the large-scale reconstruction of old urban area, large quantities of polluting enterprises are being shutting down in the downtown area. Figure 1: Some results of the preliminary assessment carried out in Suzhou. The scope of the project consists in a preliminary assessment [2,3,4], which has been carried out by means of Analyst passive samplers [5,6,7], new

5 Air Pollution XII 545 particulate matter samplers and a conventional mobile unit, supplied from Italy. The preliminary assessment has been successfully completed in 2003 and numerous results have been reached, as shown in figures 1 and 2. According to these results, the network design has been completed in 2004: 9 fixed stations and 20 saturation stations have been sited. The latter evaluate air pollution by using the same techniques employed in the preliminary assessment. In such a way, a detailed spatial and temporal representation of atmospheric pollution can be obtained. In addition, a conventional mobile unit complements the monitoring network. In short, standard monitoring stations are reduced to a minimum in order to provide effective time resolution by using standard pollution analyzers; saturation monitoring stations, employing passive samplers and simple particulate PM 10 -PM 2.5 membrane filter samplers are employed in several locations and, thanks to their relatively simplicity and low cost, they may provide effective spatial resolution over urban area under investigation; atmospheric stability analyzers are used to provide directly the mixing properties of atmosphere and its time evolution. Moreover, the air quality management system of Suzhou includes a laboratory for chemical analysis and calibrations, plus a data centre for data collection, treatment and presentation. The Data Control Centre includes all the necessary equipment for the appropriate functioning of fixed stations and mobile units. Data validation includes procedures for accurate Quality Assurance and Quality Control (QA/QC). A new emission inventory and a decision support system are now been tested and will be implemented in the next phase of the project. Figure 2: Some results of the preliminary assessment carried out in Suzhou.

6 546 Air Pollution XII 4 Beijing ITS In order to meet the commitment under decisions FCCC/CP/2001/L.14, FCCC/CP/2001/L.15 and the Joint Political Declaration, the Italian Ministry for Environment and Territory during the extended Sixth Conference of the Parties in Bonn, July 2001, has been authorized to finance activities in developing countries to contribute substantively to the implementation of the United Nations Framework Convention on Climate Change and the Kyoto Protocol. In this framework, a specific funding agreement was signed for the implementation of an Intelligent Transport System for Traffic Air Pollution control project in the city of Beijing. The Institute for atmospheric pollution of Italian National Research Council has been appointed as implementation agency [9]. Table 2: Chinese National Air Quality Standards. POLLUTANT PERIOD STANDARD UNIT LEVEL II SO 2 year hour 0.50 TSP year PM 10 year NO CO hour O 3 1 hour 0.16 Pb Season 1.50 year 1.00 B[a]P 0.01 mg/m 3 (standard state) g/m 3 (standard state) With a total area of km 2, Beijing has a population of about 13 million people. The number of motor vehicles is about 2 million, 50% of which are oldtype ones. Tail gas emissions far exceed European Standard I, implemented in recent years. Air pollution in downtown area is relatively serious because of high population density, energy source consumption and vehicles number in built area. According to the monitoring data of the Beijing Municipal Environmental

7 Air Pollution XII 547 Monitoring Center, in 2002 the s in which Beijing met the national air quality standards accounted for 55% of the whole year. The national air quality standards are reported in table 2. The annual daily concentration of PM 10 is higher than the daily standard, as reported in table 3. Main sources of air pollution in Beijing are reported in table 4. Table 3: Beijing annual daily concentrations Year PM 10 (mg/m 3 ) NO 2 (mg/m 3 )SO 2 (mg/m 3 ) Table 4: Main sources of air pollution in Beijing (10k ton/year). Sources TSP PM 10 NO x CO SO 2 Industr y Civil Other NA NA NA Traffic NA Total In the past, more efforts were devoted to environmental protection. Quality of urban environment was distinctly improved. From 1998 to 2003, SO 2 concentrations were very high in heating seasons and lower in non-heating seasons, as shown in figure 3. Therefore, thanks to the use of low sulphur coal and natural gas, the concentrations during heating seasons are decreasing in recent years. In 2001, the air content of sulphur dioxide decreased of 9.9 percent from previous years. NO x concentrations for the same period are showed in figure 4: they are higher in heating seasons and lower in non-heating seasons, but still around 100 µg/m 3. An attempt to control motor vehicles pollution has been made by giving to vehicles a green environmental protection label and by increasing to 4000 the number of LPG-fuelled buses. Nevertheless, Beijing still urgently needs to improve air quality in the built area. In this context, the Intelligent Transport System for Traffic Air Pollution control project is targeted to the implementation of a tool for the reduction of traffic emissions. The main components, as shown in figure 5, are: - A Data Centre (DC) for the integrated management of the system incorporating a simplified traffic-environmental modelling tool (TEM); - A network of air quality monitoring stations (AQMS); - A network of private traffic monitoring stations (TMS); - A Public Transport Management Subsystem (PTMS). The AQMS has been planned according to the Suzhou project, as before described. The system could allow competent authorities to perform the following action scheme:

8 548 Air Pollution XII Receive data from air monitoring stations In case of high level of pollution ask the Municipal Traffic Management Bureau to authorize traffic restrictions for polluting vehicles Manage traffic monitoring stations (TMS) to control that polluting vehicles do not enter the restricted areas Ask the public transport management subsystem (PTMS) to provide extra buses to compensate for traffic restrictions. mg/m SO Figure 3: The SO 2 daily concentrations in Beijing from 1998 to mg/m NOx Figure 4: The NO x daily concentrations in Beijing from 1998 to By keeping track of date, time and other relevant data generated every time such a scheme is activated, it will be possible to compare them and create the basis for a scientific study on the relationship between air pollution and traffic restrictions countermeasures, aimed at identifying strategies and actions for the management of private and public transport, and estimating the environmental benefit resulting from the project implementation. The project allows the identification of the pollutants distribution in a pilot area of Beijing, addressing, in the long term, the operating of the traffic flow

9 Air Pollution XII 549 management system by limiting the access of traffic pollution sources and better managing public transport. According to this requirement, the main operation strategies are: - measurements of pollutants concentrations in ambient air; - measurements of traffic pollutants emissions; - setting-up of a transport and environmental simplified model able to simulate in different scenarios the mobility and calculate the relevant vehicles emissions; - monitoring of traffic sources; - management of public transport. The project is ongoing: feasibility study and system design were completed at the end of 2003 and the implementation phase has now been started. Figure 5: Configuration of ITS-TAP in Beijing. 5 Conclusions Since forecast growth in vehicles numbers poses an enormous challenge solutions will require cooperative action at the global, regional, and urban scale. Roads are public space and vehicle ownership does not equate to right of use. As changes to systems of government have failed to keep pace with the expansion of mega cities, a political leadership is needed to cut through overlapping and conflicting jurisdictions and short-time horizons. Cleaner Vehicle Technology by itself is not sufficient. Comparable effort must now go into Intelligent Transport Systems to optimize traffic movement and use of road space. Improvement in air quality must look to integrate assessments, which consider all abatement options including technology. Experiences in some cities show that radical and integrated packages of transport measures, based upon management of road space and an enhanced role for high quality bus and rapid transport systems can deliver efficiency and equity and be economically, environmentally, and socially sustainable. However, this is not possible without strong political leadership.

10 550 Air Pollution XII Therefore, transport and air quality must be better integrated at the policy level. While in many cities in the developing world the immediate focus may be on industrial and indoor emissions, anticipatory responses to growth in transport are needed. In the developed world, mandatory air quality targets, which undermine cost-effective, locally relevant actions, need review. Long-term solutions involving major infrastructure, resources, and altered priorities are now required. References [1] Allegrini, I. & Costabile, F., A new approach for monitoring atmospheric pollution in urban environment. Proc. Of the Int. Seminar Urban Air Quality Management, 21st-23rd October 2002, Sao Paulo, Brazil. [2] Council Directive 00/69/EC of 16 November 2000 relating to limit values for benzene and carbon monoxide in ambient air, Official J. of European Communities, No L 313/12 13 December [3] Council Directive 96/62/EC of 27 September 1996 on ambient air quality assessment and management, Official J. of European Communities, No L296/55-21 November 1996 [4] Council Directive 99/30/EC of 22 April 1999 relating to limit values for sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter and lead in ambient air, Official J. of European Communities, No L 163/41 29 June [5] De Santis, F., Vazzana, C., D Angelo, B., Dogeroglu, T., Menichelli, S.& Allegrini, I. Validation and use of a new diffusive sampler for ozone assessment in the Lazio Region, Italy, In: Air Pollution X. C.A.Brebbia & J.F.Martin-Duque Eds., WIT Press, 2002, pp [6] De Santis, F., Dogeroglu, T., Fino, A., Menichelli, S., Vazzana, C. & Allegrini, I., Laboratory development and field evaluation of a new diffusive sampler to collect nitrogen oxides in the ambient air, Anal. Bioanal. Chem., Vol.373, 2002, pp ; on-line: 3 Luglio [7] Bertoni, G., Tappa, R.& Allegrini, I., Assessment of a new passive device for the monitoring of benzene and other volatile aromatic compounds in the atmosphere, Annali di Chimica, Vol.90, 2000, pp [8] Allegrini, I., Ianniello, A. & Costabile, F., Area Saturation Monitoring of atmospheric pollutants by means of passive samplers and diffusion denuders. Proc. Of the 14th Int. Conf. on Air Quality Assessment and Policy at local, Regional and Global scales, Dubrovnik, Croatia, pp.300, 6-10 October [9] Allegrini, I. & Costabile, F., Traffic air Pollution monitoring system. Proc. Of the Integrated Program on urban, regional and global air pollution, Seventh workshop on Mexico City air quality, January 19-21, 2004 and Of the Joint meeting with IUAPPA, Mexico City, January 22-23, 2004.