Common standards needed for Low Emission Zones

By: Alan Bunting, Thursday, June 18, 2009,

AutomotiveWorld.com

Low Emission Zones (LEZs) have been established in numerous cities in Europe. Their aim is entirely laudable – to minimise noxious emissions from vehicle exhausts in areas where traffic congestion is rife and where, in consequence, air pollution is most likely to rise to levels injurious to health. The vehicle ‘qualifications’ required for operating in each designated zone are at present set almost unilaterally by the urban authority. In most cases permitted maximum emission levels from different categories of vehicle, in practice especially diesel-engined trucks vans and buses, are incorporated into local regulations.

At the last count there were some 60 European cities – or urban authorities – imposing emission-related restrictions on vehicles entering their central areas. Some have imposed quite arbitrary requirements, most notably the fitment of a particulate trap, sometimes without specifying, quantifiably, an emission limit which such a filter must achieve. And often there is no provision for ensuring its ongoing performance in the face of potential clogging – a notorious problem in stop-start traffic where exhaust temperatures can struggle to reach catalyst ‘light off’ level.

Critics say that too many LEZs have been set up more as a high-profile gesture, with political overtones, helping to secure votes for the party in power from environmentally-aware local taxpayers. That may be so in some cases. But an equally serious accusation is that LEZ requirements, and the accompanying scale of the penalties imposed for non compliance, are being determined by officials with little understanding of the technical factors affecting exhaust-derived pollution levels.

For vehicle manufacturers and those seeking to adapt older, ‘dirtier’ vehicles to meet the rules, there are no quantified and universally accepted LEZ emission standards applicable across the EU, in the same way that (currently) Euro 4 limits are applied as a minimum qualification for newly registered commercial vehicles. In other words there is a deplorable lack of co-ordination.

In consequence, available emission-reducing R&D resources must be spread much more thinly than everyone would like, as manufacturers strive to meet a multiplicity of different LEZ requirements. In some cases, where quantified limits are set, the particulate matter (PM) level is the only concern of the authorities, to the exclusion, most obviously, of oxides of nitrogen (NOx). London is a prime example. Other cities in the UK, for example Norwich, have set a NOx limit for buses (but not trucks) entering their LEZs, paying no heed to their PM emissions.

Elsewhere in Europe, quite different, but still often unco-ordinated, LEZ entry qualifications apply. In Germany there is at least some agreement between about 40 cities and towns which operate schemes based on EU legal limit standards – Euro 2, 3 and 4 – with every vehicle having to display an appropriate coloured windscreen sticker entitling it to enter corresponding parts of urban areas identified by roadside signs. LEZ schemes in the Netherlands and Denmark require a basic Euro 4 vehicle qualification, but with a let-out clause for older Euro 2/3 compliant vehicles fitted with an ‘approved standard’ PM trap.

There is clearly an urgent need for common LEZ requirements across the EU, which are genuinely ‘cleaner and greener’ than the accepted ‘Euro’ standards set for general vehicle operation outside urban areas. Manufacturers could then justify worthwhile investment in further refining engines and aftertreatment packages able to be marketed internationally.

The opinions expressed here are those of the author and do not necessarily reflect the positions of Automotive World Ltd.

Published on Thursday, June 18, 2009