city centre no cars

The Challenge of Air Quality

Prof. Edward Mallia

A few weeks ago there was ringing announcement from the mayors of four large cities: Madrid, Paris, Athens and Mexico city: they will eliminate diesel cars from the city centres by 2025.  Just recently Madrid and Paris, after a number of high-pollution episodes in early December, have imposed an even-odd number plate filter on private cars, to operate while a smog episode lasts and in the case of Paris provided free public transport. Paris has also taken a longer term measure of banning cars from the roadway running along the bank of the River Seine for 6 months.  Oddly enough, similar smog episodes over London produced no better official response than to tell Londoners to breathe less often.

Meanwhile at the other end of Eurasia, the major cities in central China have been gripped by major smog events caused by traffic emissions with much help from industry.  Government response has been to close down schools, ban cars from city centres and enforce temporary close downs of steel making and cement plants.  But there have been calls, and more important action by private companies to persuade commuters in the major cities to return to the bicycle.

For Paris, Madrid and Athens, the spur for a 2025 ban on diesel cars may have come from the rather strange course of action taken by the European Union in the wake of the VW doctoring of emissions from diesel engines. The US Environment Protection Agency took an uncompromising line: the imposition of a huge fine on VW and the gradual recall of VW models for removal of the offending software responsible for modifying the diesel emission test results.

The EU and Europe in general were in a slightly different position, in that the installation of the offending VW software seems to have been less widespread.  But the official expressions of horrified disbelief at VW trumpery were countered by a number of well-known testing organisations.  These had been pointing out that the static test conditions were not representative of real road driving as far as emissions were concerned.  For NO2, actual emissions were 3 to 5 times higher than the official results.  To make matters worse, the EU rules about installation of particle filters on diesel exhausts were subject to much evasion, casting further doubt on the quality of the emissions testing.

The EU was clearly reluctant to take action. Quite early on VW announced it would be cutting 30,000 jobs world-wide.  Suddenly the European Parliament stepped in with an agreement to relax existing regulations, giving the car industry a period of at least 18 months for it to come in line with the Euro 6 standards which supposedly have gone into force in Sept 2014.  The emissions testing was to be done under conditions representative of actual road driving so as to eliminate the ‘old’ gap present even without intervention of the VW software. Yet the relaxation represented a severe setback to required improvements to air quality just at the point when the push for improvements seem to be increasing after repeated determinations of the deleterious health effects and costs thereof caused by poor air quality particularly in large conurbations.

There are other implications of this relaxation. One is the effect on the drive to lower the average car emissions of CO2 to below 95g/km by 2020, a measure which has in any case run into German objections. There is no way that diesel CO2 could be cut back in the face of a relaxation on pollutant emissions.  Resort to first generation bio-fuels, once seen as the up-coming solution has now run into the ground as the overall CO2 emissions of these turns out to be significantly larger than those of mineral diesels.  Second generation bio-fuels, those that either utilise waste streams or vegetable sources that do not displace food production may plug that gap, however. That is if the auto industry does not commit suicide by, for instance pressing on with direct injection petrol engines which in their present design stage emit more particulates than diesel engines.

Individual cities and countries have tried and continue to try adopting radical solutions. Oslo has started work to ban cars from the city centre by 2020; the Dutch and German parliaments have both started moves to legislate fossil fuel cars out of existence by 2025-2030.  The ultimate aim it is said, is to have all-electric transport both inside cities and between cities.  Even VW shareholders have exerted pressure on VW to move as fast as possible in that direction. But Shell and VW have combined to plead for a biofuel period until the electric sun rises.  So the “game” looks like it is finely balanced at the moment.  Perhaps action by individual cities will provide the key to a good solution.