environmental protection | Spring 2002 | EPndvrnoo ovl.t.1ie3 r2co tnimoenn tal ran s = S ~~ Q S .—< > bvh) o ‘ nSoacli ib eat Ce Pd oh erly LRTAP — Feasibility of Global Integrated uart Hay y; e Meteorological Challenges in Urbar tqh e e Defining Odour Control Stack Hei. % es clean air DARA AR ORO RE ER EE MER ERLOEN ALELRLLAR LRA ELLA ORR RAE RLALERELLELLRLERLARLERSRRBRLIAPRLARLPREALRLALB BEB APE AES | Online! \Created by NSCA in partnership with East Sussex County Council, our new online itravel calculator aims to show everyone how they can: | reduce the impact of road transport get fitter save money || O ur road transport emissions calculator works out annual emissions of CO2, NOx and PM10 | E3 produced by daily travel and compares them to a national average. |4 The car cost calculator adds up all the annual costs of car ownership, _and the calorie calculator demonstrates how you can use your energy | to get fitter while saving fuel. The calculator can be used by |e mployers to encourage employees to travel greener, by schools considering reducing the impact of the school run, and by anyone |w ho needs a bit of an incentive to drive less! i&/ You'llfinditat http://www.travelcalculator.or $% Reserve the date now - Environmental Protection ZO0O2 Monday 7, Tuesday 8 and Wednesday 9 October Glasgow Royal Concert Hall The key environmental protection event of the year. cover Ii Vol. 32 Spring 2002 clean air Contents SPRING 2002 lean Air -. VOLUME 32. CLEAN AIR ISSN 0300-5734 Publishing Director: Richard Mills CONTENTS Secretary General, NSCA Deputy Secretary, Finance & j ; Administration: Peter Mitchell Editorial 3 Deputy Secretary, Policy & Development: Tim Brown je é Long Range Transport of Air Pollution: Report of a Commissioning Editor & LEP D $ Policy Officer: Tim Williamson Feasibility Review of Global Integrated Assessment cae Inte:r national Union of Air Pollutixoen Prevention & Se con Environmental Protection Associations 5 Loveday Murley Advertising (rates on request): Sally May Meteorlogical Challenges in Urban Air Pollution CLEAN AIR is the official D.R. Middleton 14 journal of the Society but the views expressed in contributed articles are not necessarily d d by the Society. ht or el ate Use of Dispersion Modelling to Define the Height of Odour CLEAN AIR is issued free to Control Stacks Members and Representatives of P.S. Childs and D.L. Hall 20 Members. CLEAN AIR subscription: 2002 — £32.00 an cy eae Examining the Potential for Local Authorities in Norfolk Abstraction and quotation of to Reduce PM. Concentrations in their Areas matter are permitee ,c acebe, Winer’ Dr. Tim Chatterton and Dr. Steve Dorling 25 stated, provided that due acknowledgements are made. CLEAN AIR is printed and published ; ; ; ae in England by the Factors Influencing Indoor Air Quality — Quantifying the National Society for Clean Air Roles of Domestic and Outdoor Sources of Air Pollutants and Environmental Protection ; 44 Grand Parade, Brighton BN2 9QA Steven Naylor 30 Tel: 01273 878770 Fax: 01273 606626 Email: [email protected] Website: www.nsca.org.uk Advertiser: University of Leeds 4 The National Society for Clean Air and Environmental Protection produces information, organises conferences and training events, and campaigns on air pollution, noise and environmental protection issues. Founded in 1899, the Society’s work on smoke control led to the Clean Air Acts. More recently NSCA has been influential in developing thinking on integrated pollution control, noise legislation, and air quality management. NSCA’s membership is largely made up of organisations with a direct involvement in environmental protection: industry, local authorities, universities and colleges, professional institutions, environmental consultancies and regulatory agencies. Individual membership is also available to environmental specialists within industry, local authorities, central government, technical, academic and institutional bodies. Members benefit from joining a unique network of individuals who share an interest in a realistic approach to environmental protection policy; from access to up-to-date and relevant information, from reduced fees at NSCA conferences and training events. They contribute to NSCA’s regional and national activities; to environmental policy development; to translating policy into practice; to the Society’s wide-ranging educational programmes. Vol. 32 Spring 2002 1 Officers clean air NATIONAL SOCIETY FOR CLEAN AIR AND ENVIRONMENTAL PROTECTION (Founded 1899) Registered Charity, Number 221026 PRESIDENT Mr. J. Speirs CBE IMMEDIATE PAST PRESIDENT Mr. D. Osborn CB VICE-PRESIDENTS Professor The Lord Hunt; Professor R. Macrory HONORARY VICE-PRESIDENTS Mr. A. Bennett MP; Prof. Dame Barbara Clayton DBE; Mr. K. Collins; Earl of Cranbrook DSc, DL; Dr. R.N. Crossett; Mr W. David; Mr. J. Edmonds; Nigel Haigh; Dr. C. Jackson MEP; Air Commodore J. Langston CBE; Prof. The Lord Lewis KT, FRS; Sir John Mason CB, DSc, FRS; Lord Nathan; Mr. S. Norris; Mr. L. Poole BEM, JP; Sir Hugh Rossi; Sir Crispin Tickell GCMG KCVO; Mr. G. Wardell CHAIRMAN OF THE BOARD OF TRUSTEES Mr. P. Cooney DEPUTY CHAIRMAN OF THE BOARD OF TRUSTEES Mr. K. Leyden CHAIRMAN OF COUNCIL Mr. J. Gyllenspetz IMMEDIATE PAST CHAIRMAN OF COUNCIL Dr. M. O’Leary DEPUTY CHAIRMEN OF COUNCIL Ms J. Light; Cllr V. Bloxsome HONORARY TREASURER Mr. K. Horton SECRETARY GENERAL Mr. R. Mills Honorary Secretaries of NSCA Divisions Scottish Division: Alastair Brown — Telephone: 0141 287 4974; Email: [email protected] Glasgow City Council, Protective Services, Nye Bevan House, 20 India Street, Glasgow G2 4PF Northern Ireland Division: Mervyn Fleming — Telephone: 01232 494 570; Email: [email protected] 67 Kilwarlin Road, Hillsborough, Co. Down BT26 6EA Northern Division: Jeff Duffield — Telephone: 01642 264 154; Email: [email protected] Middlesbrough Borough Council, Public Protection & Trading Standards, PO Box 68, Melrose House, Middlesbrough TS1 1Q$ North West Division: John Dinsdale — Telephone: 0161 911 4492; Email: [email protected] West End House, West End Street, Oldham OL9 6DW Yorkshire Division: Frank Price — 205 Shirebrook Road, Sheffield $8 9RP; Email: [email protected] West Midlands Division: John Sweetland — Telephone: 01952 202558; Email: [email protected] 30 St. James Crescent, Stirchley, Telford TF3 1BL East Midlands Division: Dr. Bill Pearce — Telephone: 01623 463463, ext. 3139; Email: [email protected] Environmental Health Services, Mansfield DC, Civic Centre, Chesterfield Road South, Mansfield, Notts NG19 7BH South East Division: Rob Gibson — Telephone: 020 8583 5211 (work); Email: [email protected] 9 Kingston Road, Wimbledon, London SW19 1JN South West Division: Peter Fryer — Telephone: 0117 922 4488; Email: [email protected] Health & Environmental Services, Bristol City Council, Create Centre, Smeaton Road, Bristol BS1 6XN Wales Division: Alan Brown — Email: [email protected] Caerphilly CBC, Directorate of Environmental Services, Civic Centre, Pontllanfraith, Blackwood, Gwent NP12 2YW 2 Vol. 32, Spring 2002 clean air Editorial E d i t o r i a l A PROBLEM SHARED In this issue, we focus on recent progress made by the International Union of Air Pollution Prevention and Environmental Protection Associations (IUAPPA), of which NSCA is a founder member and for which it provides the secretariat. It has resolved to develop ways in which the understanding of air pollution on a world wide scale can be better quantified and understood and we report here on how that important task is being addressed. The work in Europe of the UNECE Convention on Long Range Transboundary Air Pollution has been one of the success stories of international environmental policy. However, the problems of regional ozone and particulates make it clear that the work is far from complete. Elsewhere in the world the position is far less satisfactory. In many developing countries, emissions of the main pollutants have been rapidly increasing. Long range transport means that much of their impact will be at regional and global level and institutions for collaboration within scientific, operational and political disciplines are as yet unequal to the challenges. As one of its main priorities, IUAPPA has been undertaking a major review of scientific, technical and policy requirements at regional and global levels. In this issue’s first article, we publish a summary of the reports of the preliminary stages of this project, together with the Resolution passed by last year’s World Clean Air Congress on the action that now needs to be taken to address the problems. Work on the programme is overseen by IUAPPA’s Director General, Richard Mills from NSCA, and much of the work undertaken by Teresa Gonzalez of Imperial College. For further information they can be contacted at NSCA’s head office. In the remainder of the issue, we cover some of the other important topics within the air pollution field, albeit of a more domestic nature. Some of the key questions to come out of the recent round of local air quality review and assessment concerned meteorological data. In response to some of these concerns, the Met Office, along with other agencies across Europe, is investigating the use of met data in urban settings. Dr. Doug Middleton reports on the COST 715 project, and sends out a request for met observations in or near urban areas. We also carry reports on three other issues. The first is on the use of dispersion modelling to assess chimney height for odour dispersal, a hot topic for those applying for or writing process permits under IPPC/IPC. Dr. Tim Chatterton looks at PMi reduction strategies in Norfolk, uncovering an intractable problem, and Steve Naylor reports on indoor air quality in West Cumbria. Next Issue: Local Sustainability Vol. 32, Spring 2002 3 advertisements clean air CONTINUING PROFESSIONAL DEVELOPMENT SHORT COURSES Wednesday 22 May 2002 Industrial Air Pollution Monitoring 18 — 20 March 2002 poise action day! Noise Management of Emissions Monitoring, Action Day Techniques and Instrumentation Air Pollution Monitoring Exhibition Noise Action Day aims to: by equipment suppliers and consultants a Promote practical solutions to everyday Tuesday 19 March 2002 10.30 am - 2.30 pm neighbour noise problems FREE ENTRANCE FOR VISITORS aaPromote communication and consid- Combined Heat and Power in eration between neighbours Encourage local authorities and mediation Industry and Commerce services to inform the public of services PLANT DESIGN AND PERFORMANCE, SAFETY available AND ENVIRONMENTAL ISSUES 2aaEducate and inform both noise makers 9-10 April 2002 and noise sufferers about noise reduction For other courses and full and part time MSc programmes, visit our aa Encourage everyone to take a quiet web site at: www.leeds.ac.uk/business/cpd.htm moment to consider the noises they For further details: Alison Whiteley, CPD make and the noise that affects them — Unit, SPEME, University of Leeds, Leeds and what can be done to reduce the LS2 9JT.Tel: 0113 233.2494 Fax:'233 impact. 2514 For a NAD information pack: Email: [email protected] Tel: 01273 878770 The University of Leeds promotes excellence Email: [email protected] in teaching, learning and research New for March 2002 Leaflet - Reducing the Impact of Motor Vehicles, £7.00 - 100, £50.00 - 1000 A new leaflet covering pollutants from motor vehicles, legislation and how to minimise the impact of motoring. Factsheet - Contaminated Land and Brownfield Land, single copy free of charge. An outline of issues around ‘used’ land. Seminar pack - Asbestos, preparing for the new regulations, £15.00 Available papers and slide presentations from NSCA’s seminar held at the NEC, 12 February 2002 Teaching Pack « Hear This! £9.99 A noise pollution teaching pack for primary schools. Includes activities on noise and sound to support Science, PSHE and Citizenship. It includes a colour poster of the ear, CD of noises, sound survey and a weeks worth of assembly ideas. Available from NSCA 44 Grand Parade, Brighton BN2 9QA Tel: 01273 878770 Fax: 01273 606626 Email: [email protected] Vol. 32, Spring 2002 clean air Global Integrated Assessment Long-Range Transport of Air Pollution Report of a Feasibility Review of Global Integrated Assessment International Union of Air Pollution Prevention & Environmental Protection Associations This paper summarises work undertaken by the Union to the UN/ECE Convention on Long-range Transboundary Air explore the scope for establishing a more effective Pollution (CLRTAP), and there is an emerging interest in its political and institutional framework, at regional and application at other levels, including the global scale; global level, to tackle the long range transport of air e as early as 1992, as part of the Rio Process, Agenda 21 pollution; and to explore how far recent developmentsi n called for the extension of the CLRTAP experience to other the underlying science provide a basis for this. regions of the world. There is a need to review how far this is progressing. BACKGROUND These considerations pointed, inter alia, to the need for a study which could review general trends and issues and in The project represented a response by the International particular review the feasibility of the wider application of Union to a number of themes and issues which it recognised integrated assessment modelling to long-range transport at as of increasingly widespread concern, in particular: the global level. However it became apparent at an early e air pollution remains a serious source of health damage stage that if the review was to be of practical value it was and environmental degradation and in many areas its important that the ‘global scale’ should be construed widely impact is increasing. Many air pollution problems are to cover both the possibility of a single assessment for the primarily local or regional in their origin and impact, but world as a whole, and the possibility either of separate background levels associated with the long-range hemispheric assessments or of a linked range of regional transport of pollutants make a substantial contribution studies which might in relevant circumstances sum to a and need to be addressed. This requires increased wider global perspective. At all stages therefore the review co-operation at global and regional level. looked at the implications of the analysis for the separate _ e rapid decline in emissions of some of the more important options of a single global assessment and of a linked series of transboundary pollutants within the UNECE area is being regional assessments. counterbalanced by the very rapid increases elsewhere, It was necessary also to clarify the interpretation of the posing issues which were new in both their scale and their concept of ‘feasibility’. It was concluded that this should scope. Air pollution associated with large-scale forest burning has become a new and serious problem. also be construed as widely as practicable. Hence feasibility was taken to apply at three separate levels: e work on stratospheric issues, and in particular their relationship to long-range transport of pollution at e a theoretical level, which looks at how far systems and tropospheric level, is meanwhile changing the context in processes not previously applied at global scale could be which tropospheric issues need to be addressed. Climate applied at that level; change has given added impetus to the global scale in air e a practical level, which looks at the availability of data, pollution policy and the need to address pollutants such skills and resources to deploy and calibrate any model at as SO, at that level is beginning to alter the context within alternative levels globally and in other regions; which regional assessments and management strategies are seen. At the same time a number of studies, principally e and, finally, a political level, which seeks to assess how far in the United States, are beginning to reflect the need now outcomes would be likely to prove deliverable and to inter-relate the metropolitan, regional and global levels effective in policy terms. of assessment. The structure of this report largely follows these three levels e meanwhile there has been rapid progress at the scientific of feasibility: level. ‘Integrated assessment’ is now established as an important tool for bringing together scientific and policy e it first reviews the theoretical feasibility of applying the analysis in the pursuit of solutions to complex and assessment process at global and regional levels, and the intractable problems. It has now been applied with some implications for the nature and robustness of any success to air pollution problems at regional level within conclusions that might be drawn; Vol. 32, Spring 2002 Global Integrated Assessment clean air e it then reviews the state of technical understanding and conflicting political interests. Subsequently — political data availability on the wide range of factors which must opportunities were widened by important developments in be played into an integrated assessment process, at both science and practice within Europe and North America which global and regional levels, including current and projected were crucial to progress. While CLRTAP itself stimulated a emissions, eco-system sensitivity, pollutant transport and wide range of scientific activity, it was also able itself to deposition, and abatement options and costs; benefit from subsequent developments which helped provide a more secure base for the development of the Convention e finally it discusses the key cultural and_ political than could have been anticipated at the beginning. In sum, considerations which could have a bearing on the the early commitment of the initiative to the neutral ground practicality of applying the process at global level, and in of scientific assessment meant that a substantial, strong and other regions. enduring basis for the programme could be progressively To set the scene, however, the report first reviews very assembled outside of the mainframe of policy controversy. briefly some of the conclusions which may be drawn from UNECE experience suggests however that a particularly the experience, in which the UK Government has been crucial requirement is the emergence of an agreed single closely involved, of the Convention on Long-range Transport base model, in this case the RAINS model. This was critical to in Europe. This experience represents the principal practical the medium and long term success of the Convention in that learning ground for the issues addressed in this report and can help to clarify some of the key considerations. it provided the objective mechanism for narrowing political disagreement. Were there a large number of different models, markedly competing in their assumptions, it is UN/ECE EXPERIENCE: THE CONVENTION ON LONG exceedingly unlikely that there would have been a sufficient RANGE TRANSBOUNDARY AIR POLLUTION (CLRTAP) degree of technical consensus to allow policy progress. In the event, most other models became little more than It is to be expected that appropriate approaches to tackling helpful critiques at the margins of elements of the core the regional management of transboundary air pollution will RAINS models. In effect, the contribution of the RAINS vary significantly from one region to another. They need to model was to narrow options to a feasible range for reflect the cultural, economic and political circumstances of negotiation, and it is arguable that it is this that was the the particular region. Nevertheless, in considering the scope critical factor in progress. It was arguably even more for progress globally and in particular regions, it is useful to important than the emergence, at an earlier stage, of the have in mind as background the experience within the ‘critical loads’ approach which had been crucial in allowing UNECE region to which the Resolution at the Rio Conference a bridge to be developed between environmental processes referred. There are several possible lessons. and policy instruments. First, while the problem of acid rain in Europe — on which It seems unlikely, however, that scientific development the UNECE Convention first focused — became a significant could have been transformed into political progress without area of international policy controversy, it was one which the contribution of supportive economic change. It was cut across the major political alliances and tensions in the crucial to success that many of the contributions sought continent. It could therefore be addressed outside the main from individual Member States came to be recognised as in political divisions of Europe. Indeed it was focused at line with their own policy aspirations on other fronts. In its sharpest between otherwise allied countries in the particular, LRTAP almost certainly could not have been so Western half of -the continent. Subsequently through successful were it not for changes to energy policy in periods of deep political controversy in Europe, the issue European countries which automatically made _ the could be constructively pursued without jeopardising environmental gains possible. wider continental political positions. Indeed the LRTAP Convention offered certain wider These various considerations provide an indication of the Opportunities in political terms in that the countries range of factors which may be relevant to the potential involved, straddling the main political conflict lines in success of future attempts to apply integrated assessment Europe, could utilise it as a relatively safe framework for elsewhere and in different circumstances. They cannot be continued contacts, even at periods of very high tension on ranked in any strict sense, but include, in particular: other more major policies. This was made easier, however, e a high degree of consensus on the intellectual, scientific by the fact that on this issue leadership did not naturally fall and technical underpinning for policy debate, which in to any of the major protagonists in the then Cold War, but particular narrows the range of available options; fell largely to Scandinavian countries, who were seen as strongly internationalist, politically less partisan, and as e a political climate which ensures that the issue is seen as having a strong tradition in international bridge-building. outside any established pattern of political conflict, and This suggests that on this issue smaller, relatively non- one where there is leadership acceptable to all political aligned countries can — and perhaps must — contribute the interests; essential element of acceptable international leadership. e and most of all, compatibility of objectives and proposed The scope for progress was further enhanced by the extent to measures with wider philosophical trends and economic which the issue could initially be seen as an international processes, which appear to validate and give wider scientific challenge rather than — primarily — as an area of acceptability to them. 6 Vol. 32, Spring 2002 clean air Global Integrated Assessment Clearly any such lessons from UNECE experience cannot be divergences of perception and attitude, which might in turn translated directly to other areas and periods. Application of create greater political and negotiating difficulties. In integrated assessment at the global level or in other regions principle this seems likely, but the evidence is far from clear: will raise a wide range of quite different considerations. it could as well be argued that distance would avoid options However, so long as not interpreted rigidly, these conclusions being narrowed by a history of local distrust. from European experience can provide a helpful background On the other hand a number of theoretical advantages are for assessing feasible development elsewhere. clearly discernible from approaching integrated assessment at a global level: THEORETICAL FEASIBILITY e it will deal better with boundary areas; Against this background the various dimensions of e it may also be a more relevant context for considering feasibility identified earlier can be assessed. increasingly significant factors such as aircraft and shipping; The first issue is how far there is a common scientific and intellectual framework which could provide the basis for e it allows a clear link to climate change; enhanced multi-national efforts for addressing transboundary e and it can bring to light stresses between different pollution at global and regional scale, and what any such environmental systems which might not otherwise be framework might imply for how global and regional processes evident. should develop; and how far there might in principle be considerations which might point to proceeding at global or Balancing these various considerations leads to the regional level. following conclusions, in principle, about the theoretical feasibility of global integrated assessment: Integrated assessment is essentially a theoretical construct which offers a framework for drawing together in a e there is no theoretical case which should preclude coherent manner a range of diverse factors interacting in a assessments being conducted at the global level; complex manner. In essence therefore it should offer a e indeed there are a range of factors, such as boundary mechanism capable of application to air pollution transport conditions, aircraft and shipping, and relationship to at any level, including the global, and to any region. other environmental systems which, given very high levels However the feasibility review concluded that the nature of of very long-range transport, might suggest that the the model will have important implications for how far it theoretical case for moving straight to integrated global can be successfully used at different levels, and these will assessment could become strong; need to be recognised in future applications. e however, the central benefits of the process are likely to The key consideration is that the essential purpose of be diluted, above a certain level, by increasing scale. As integrated assessment is to permit economic optimisation, the scope for worthwhile economic optimisation narrows, that is to identify the least cost option for abating the process seems likely to be prey to the law of emissions, taking into account the range of environmental diminishing returns. sensitivity, i.e. critical loads and levels. However, it is in This may suggest the need to proceed in a balanced and general likely that the impact of emissions will be most integrated way at both global and regional level. The marked in those areas relatively nearer, rather than more questions then are how far, at each level, the scientific and distant from, the source. It can be argued that it will political conditions exist for progress, and what institutions therefore generally be more cost-effective to abate those might best promote this. emissions-close to the area of impact which is the subject of policy concern than those more distant. The broad implication of this must be that, as a rule of thumb, the PRACTICAL FEASIBILITY wider the area for an integrated assessment becomes, the less direct value it is likely to have in economic optimisation Tackling long-range and transboundary transport of air terms. This might, for instance, favour the regional as pollution depends on the availability of a scientific against the global level of analysis. assessment system — such as integrated assessment modelling — to predict pollution impacts and guide policy While this proposition may have some force, a number of intervention. That depends in turn on scientific skills and qualifications need to be noted. In the first place, it may be data availability across the various components of the qualified by marked differences of abatement cost. Even if modelling process, in particular: the source and the receptor are far distant, extreme differences in abatement costs might nevertheless justify, e the generation of quantified emissions data and from the perspective of the receptor, abatement activity at projections; such distance; and currently there are, of course, gross e understanding of ecosystem sensitivity to the relevant disparities between countries and regions in abatement pollutants; costs. Equally, the relative scale of the emission between areas is also likely to be significant. e capacity to measure or model long-range transport and deposition; and A further constraint in principle on very large-scale or global exercises might appear to be the risk of greater e the knowledge of abatement methods and costs. Vol. 32, Spring 2002 Global Integrated Assessment clean air The review assessed in some depth the availability of useable in this seems slow, although a good deal of impetus was data in each of these areas, at global and regional levels. The given by the RAINS-Asia programme. broad conclusions are briefly summarised here. The position is mitigated to some extent by the existence of a number of global assessments. UNEP-RIVM has created broad maps of ecosystem sensitivity to acidification and Emissions eutrophication, which help identify areas of the world, such The overall conclusion from the technical review is that as central parts of South America, Western and Southern quantification of emissions is now well advanced, especially Africa, and Siberia, as areas that may potentially be affected in Europe and the USA, and is making relatively rapid by acidification and eutrophication. However it must be recognised that the critical loads used for these regions are progress in other parts of the world. Absence of emissions full of assumptions and very often just an extrapolation data would therefore be unlikely, in the next few years, to from European values. There are also a number of other pose a significant constraint on a global integrated useful initiatives: for example, WHO has recommended assessment or on the rapid expansion of regional activities. guidelines for ozone for protection both of human health Europe and the USA have for some years been creating and crops, and levels have been mapped for Europe and the annual emission inventories of the major pollutants world generally to identify potential risk areas. potentially the subject of global integrated assessment Overall however it is clear that ecosystem sensitivity is a (notably $O2, NOx, NHs, CO, CO., CH., HM, POPs, VOCs and, much more subtle and difficult issue than emissions, and one more recently, particulates). National emission inventories which is much less well researched and understood outside are not common elsewhere in the world, but the experience Europe. This is particularly significant because there are some of the RAINS-Asia study suggests that it is not a grounds for believing that ecosystems in the Southern prohibitively difficult task to generate estimates of hemisphere may be intrinsically more sensitive to emissions for the broad purposes of the modelling processes, acidification than in the Northern hemisphere, for complex even if these have subsequently to be continuously refined. physical and chemical reasons. The relative absence Such national data sets are also now complemented by elsewhere of substantial and detailed analysis on the initiatives at global level. The IPPC has created a global European level therefore represents a formidable obstacle to database of greenhouse gases, the Global Emissions confidence in the early practicability of global studies, and — Inventory Activity (GEIA), which involves gridded global probably to a lesser extent — a constraint on the development emissions inventories of the main gases and aerosols emitted of regional systems. into the atmosphere. The EDGAR database produces gridded emission inventories of GHG, NH;, and pollutants causing Long-range Transport and Deposition acidification and ozone formation. As the core of the modelling process, it is not surprising that As the technical reports of the project indicate, however, globally the picture here is complex. this encouraging picture needs qualification on several fronts. More systematic and comprehensive data remains Work is advanced in Europe, with the key component being desirable for most regions outside Europe and North the EMEP source/receptor relationships for acidifying and America, and everywhere there is a need for better eutrophying pollutants, photo-oxidants, POPs and heavy validated emission estimates of NH; and ozone precursors, metals. Further, work is now currently in hand on the NO, and VOCs, heavy metals and POPs. creation of similar source/receptor matrices for particulates. The estimates of deposition which these have Prediction will of course continue to represent a formidable allowed provide the basis not only for the RAINS model, but challenge, even though IPPC has long-term emission also for ASAM, CASM and HARM. scenarios for greenhouse gases in its Special Report on Emission Scenarios (SRES). However, while the uncertainties In North America broadly similar studies have taken place here mean that the integrated assessment process might under the NAPAP Programme, and this has generated maps need to work on a wider range of illustrative scenarios, this of pollutant deposition for the US. There are also agreements need not remove its value to policy. with neighbouring countries, notably Canada and Mexico, regarding the transboundary aspects of most pollutants, especially acidifying substances and precursors of NO;. Ecosystem Sensitivity The position in Asia, and even more elsewhere, is more Here the position is less encouraging, both in relation to challenging. However in Asia there are now many acidification and eutrophication, and to effects of heavy independent studies which could merit aggregation. Indeed, metals and POPs. The subject has been very extensively when the RAINS-ASIA project calculated source/receptor matrices and deposition of acidifying pollutants for South- addressed in Europe (through the UNECE critical loads approach) and in affected regions of the United States East Asia it reached the encouraging conclusion that the (through the US’s National Acid Precipitation and results were broadly in line with local and regional studies. Assessment Programme — NAPAP). However, in other parts Certain studies at global level also now make a valuable of the world there are only disparate local and regional contribution. For instance, the UNEP-RIVM Project on studies that would need to be aggregated. Globally progress acidification and eutrophication has estimated deposition 8 Vol. 32, Spring 2002