May 2011 environmental SCIENTIST Journal of the Institution of Environmental Sciences Air Quality & Health 17149 Environmental Scientist Ma1 1 26/5/11 13:09:14 2 environmentalSCIENTIST • May 2011 PM10 QUESTION TImE PROFESSOR MaRTIN rently remain affected and some water environmental WILLIamS reviews the challenges bodies will take a long time to show within the air quality sector recovery. In terms of human health, the SCIENTIST introduction of the three-way catalyst on petrol cars in the so-called ‘Euro 1’ Journal of level of legislation has made large im- the Institution of provements in urban air quality since Environmental Sciences the early 1990s. This coupled with leg- islation on evaporative emissions and ISSN: 0966 8411 releases from the petrol retail chain, Vol 20 No 1 ir quality and associated together with measures on solvents, has Established 1971 policies in the UK have also reduced volatile organic compound reached a key stage in (VOC) emissions such that many toxic The Environmental Scientist provides their development. The and carcinogenic compounds have de- a forum for members’ contributions, successes of the 1956 clined markedly and peak ozone con- views, interests, activities and news, as AClean Air Act are now far behind us; centrations in ‘summer smogs’ have well as topical feature articles. Articles unlike the stark images of the earlier decreased significantly from the 1970s should be submitted to the Editor, smogs, the emergence of new problems and 1980s, when peak ozone levels Environmental Scientist, from particulate matter (PM) in the were 200 ppb or more (258 ppb in the 34 Grosvenor Gardens, early 1990s arose from increasingly so- famous 1976 summer)-such peaks are London SW1 W0DH or emailed to phisticated statistical epidemiology but now rarely above 100 ppb in northern [email protected] nonetheless led to a resurgence of inter- Europe. est in urban air quality and the associ- Views expressed in the journal are ated health problems. The UK was at However, it is now becoming apparent those of the authors and do not the forefront of action here through the that levels of some pollutants, includ- necessarily reflect IES views or policy. 1995 Environment Act and the first Air ing particulate matter (PM) (probably Quality Strategy in 1997, both of which the most important in health terms) and Guest Editors: emerged before the suite of air quality nitrogen dioxide (NO2) (the most diffi- Adam Donnan, Bernard Fisher, Julia Directives in the European Union (EU) cult in terms of achieving compliance Heaton & James Irwin in the late 1990s. In parallel, activities with EU legislation) are not reducing addressing wider scale problems of to the level expected and in some ar- Published by ozone, acidification and eutrophica- eas may even be increasing. What is The Institution of Environmental tion (excess nutrient nitrogen) led to the reason for this? Analyses in recent Sciences, 34 Grosvenor Gardens, the signing of the Gothenburg Protocol years have shown that this is attribut- London SW1W 0DH within the Convention on Long Range able to the road vehicle sector. In the Tel: 020 7730 5516 Transboundary Air Pollution and sub- last seven or eight years there has been Email: [email protected] sequently the EU National Emissions a large increase in the proportion of Website: www.ies-uk.org.uk Ceilings Directive. These activities to- diesel cars in the UK, and European, gether offered the prospect of a couple fleet. Diesel cars emit more NOx and Printed by of decades of significant improvements PM than petrol cars equipped with cat- The Charlesworth Group in air quality, in human health and in alysts. Moreover, in order to meet suc- Tel: 01924 204830 impacts on the environment, not simply cessively stringent emission limits on because of the setting of standards and PM from diesel cars, oxidation catalysts targets but because these were also ac- have been fitted and these have had the companied by source-related regulation effect of increasing the proportion of on motor vehicles through the ‘Euro NO2 in the primary emission of NOx. standards’, and on major industrial At the same time heavy duty diesel ve- emitters in the IPPC (Integrated pollu- hicles, particularly some bus fleets such tion prevention and control) Directive as in London, have fitted particle traps and related legislation. which work by using enhanced NO2 in the exhaust to oxidise the particles in There have been some notable suc- the trap to regenerate it. This too has cesses. Sulphur dioxide emissions have led to increased primary NO2 emission. reduced significantly and the acidifica- Even more significantly, recent remote tion problem in Europe has in essence sensing data (Carslaw et al., 2011) has been solved – although some areas cur- suggested that the Euro standards from 17149 Environmental Scientist Ma2 2 26/5/11 13:09:18 environmentalSCIENTIST • May 2011 3 Euro 1 to Euro 5 have had very little lic perception and opinion on the two Affairs began this process of optimal effect on NOx emissions from diesel issues is widely different. It seems un- alignment last year (Defra, 2010) and cars and light vans. All these factors likely that a theoretical economic dam- the recent publication of advice to local have resulted in fairly flat trends in NO2 age cost alone is sufficient to galvanise authorities ‘at the sharp end’ will help concentrations at urban locations influ- action; indeed the damage costs have to translate this strategic direction into enced by traffic in the UK and also in been on the table for the past five or reality. most European countries. This is caus- more years without appreciable new ing problems for compliance with the actions. The one pressure which ap- Air pollution problems are becoming EU limit value for NO2 but the conse- pears likely to generate activity, and increasingly global, both in the sense quences for public health are much less some investment, is the threat of non- of intercontinental transport of pollut- clear-the health effect evidence for NO2 compliance with EU legislation, despite ants and the need to share experiences, appears to be less convincing than for the fact that putative fines (described in science and policies on a world-wide PM for example, particularly in the vi- the media as being of the order of £300 basis. This will help to increase com- cinity of the limit value. It is interesting million with no apparent evidence for munication and spread awareness and to note that the United States Environ- such a figure) are much less than the this is a welcome development. mental Protection Agency has promul- economic damage costs. The UK has gated a standard 2.5 times less stringent never suffered a full infraction judge- In summary, there have been some im- than the EU value, despite a recent re- ment on an environmental issue, and portant success stories in recent years, view of the health effects. recent announcements suggest that but there have also been failures, and such considerations carry some weight there remain significant public health Perhaps a more significant issue is the – incentives for cleaner HGVs in last challenges to air quality managers and fact that levels of PM (particles meas- year’s budget, the announcement in the 10 policy makers in the UK, in Europe and uring 10 µm or less) are reducing less past two weeks of a £5 million fund to world-wide. The papers in this timely than might have been expected (Har- promote short-term actions in London and welcome edition of Environmental rison et al., 2008). This is partly due as requested by the European Commis- Scientist summarise the key issues ad- to the complexities of the atmospheric sion in relation to the UK’s time-exten- chemistry where reductions in the sec- sion application are cases in point. mirably. ondary aerosol components (sulphates, nitrates etc) are not necessarily 1:1 with These actions, designed as they are to Martin Williams is a Professor in Air reductions in precursor emissions, and achieve legal compliance, will do little Quality Research at the Environmen- the fact that the directly controlled pri- to improve the overall impact of air pol- tal Research Group, King’s College. mary emissions make up a relatively lution on public health. One further no- He was previously Head of the Air and small fraction of the total PM mass. table success which has been achieved Environmental Quality Division of the This means the estimates of the public in the recent past has been the inclusion Department for Environment, Food and health burden have not improved much of the ‘exposure reduction’ concept Rural Affairs (Defra) and is currently in the past five years or more, with into EU legislation which is designed chairman of the Executive Body of the the current estimate being that levels to align legislative pressures with im- UNECE Convention on Long Range Transboundary Air Pollution. Profes- of PM2.5 currently reduce life expect- provements in health impacts – which ancy by around six months across the the current standards-based system sor Williams is an Honorary Fellow of whole UK population with an associ- does not do adequately. Actions to the IES and gave the 2007 Burntwood ated economic cost of roughly £15 bil- achieve more effective measures in the Lecture. lion. Clearly more action is needed on short term however will come if public PM, but this is constrained by the fact opinion is behind them. Environmental References that there is still no clear identification Protection UK is working actively to Carslaw, D. Beevers S. Westmore, E. and Williams, M. 2011. Trends in NOx and NO2 of the most harmful components of the promote such developments, as detailed emissions and ambient measurements in the UK, PM mix, despite around 15 years or in this issue.