Counting Car Emissions - Too Much Hot Air?

Jersey's government should introduce MoT-style tests for all vehicles, according to an air quality report. The Environment Department said emissions and road worthiness checks would make sure vehicles are kept within EU standards. Currently only buses, taxis and trucks have annual tests but the study found 40% of cars do not meet EU regulations. Jersey's Environment Minister, Deputy Rob Duhamel, said vehicle standards needed to be addressed.
 
"Clearly this is not satisfactory and in order to weed out those vehicles that are perhaps more polluting than their modern counterparts I think some serious discussions will have to take place with the transport minister about the introduction of MoT tests," he said. Air quality surveys run jointly by the Health & Social Services and Planning & Environment departments help shape the States air quality strategy.
 
Transport Minister, Deputy Kevin Lewis, said he would support the idea in principle but now was not the right time. "I think the short answer is not at the moment. There is a recession on and I don't think the garages are geared up for it at the moment. "We have our own road checks carried out by DVS and the honorary police and people not keeping their cars up to standards do have them taken off the roads."
 
Deputy Lewis said in future the island might be expected to introduce tests after pressure from places like the UK and France. The transport department said there are about 100,000 cars on the roads in Jersey.
 
http://www.bbc.co.uk/news/world-europe-jersey-22692416
 
I'm a collector of odd statistics, and the last one is clearly rather a odd figure. Unless there are a huge number of visiting tourists, it is most likely the figure of 100,000 (such a curiously round number!) refers to the number of cars registered to be on the roads in Jersey. The population is less than that, and once one excludes people without cars, and children and teenagers under 17, the number will fall still further. So some people have more than one car, and this figure probably also includes hire cars and cars on garage forecourts, not all of which are out on the road all the time at once.
 
But while I will return to that figure, I'd also like to look at the main story here, and the statistics in that. The report in question is the "Jersey Air Quality Strategy and Action Plan", which is available on the States Assembly website, and this says:
 
"The greatest proportion of air pollution in Jersey is from road traffic emissions. The 2010 Sustainable Transport Policy (STP) recognises that emissions from transport are significant in the Jersey context of air quality, and presents a series of recommendations which have the potential to reduce emissions from vehicles.Transport emissions of nitrogen oxides (NOx) and particulates (PM10) present the greatest challenges to improving air quality in Jersey. "
 
The monitoring has highlighted various "hotspots" such as Georgetown in St Saviour, Beaumont in St Peter and in St Helier: First Tower, the former Bus Station, Broad Street and La Pouquelaye. Other sites identified as being at risk of elevated levels of nitrogen dioxide include Le Bas Centre, Mont Felard, Robin Place, Saville Street/Rouge Bouillon and Beresford Street
 
The report notes that "40% of vehicles on Jersey's registration system are over 10 years old and so do not meet the requirements of the Euro 3 standard". This is an emission guideline for all vehicles manufactured for sale in the EU after the year 2000. But what we don't know is how far out from that standard they are.
 
In other words, the earlier standards such as Euro 2 (1996) addressed other matters such as levels of CO2, and HC+NOx) but didn't put any limits on emissions for NOx and PM10. What we don't know is the profile of pollution from older vehicle emission. The report simply takes cars by a cut off date and says that all cars before that date do not meet the modern standards. But in fact, the situation is complicated by the development of cars over that period, and their continual improvement regardless of directives.
 
An American study noted that today' new cars emit 97 percent less hydrocarbons, 96 percent less carbon monoxide, and 90 percent less nitrogen oxide than those built twenty years ago. But the same report also notes that cars purchased in the 1990s will emit about 80 percent less hydrocarbons and 60 percent less nitrogen oxide during their lifetimes, even though they will be owned longer and driven farther.
 
California's Air Resources Board Chairman, John Dunlap noted that in 2003, new vehicles would emit only 25% of harmful pollutants coming from 1994 vehicles. But he also observed that emissions from cars and light trucks had already been reduced by more than 90% for the period from 1966 to 1994.
 
So the closer the car is to the cut off  point of Euro 3 (2000), the more likely it is to be near to that threshold. The threshold is, after all, an arbitrary one, set by politicians to reduce emissions. The figure of 40% not meeting EU regulations may be strictly true, but it does not give the whole picture. It suggests a situation which may well appear worse in terms of pollutants from vehicle emissions than it actually is. The cars prior to 2000 fit on a continuum, in which more recent usually means less polluting.
 
Moreover, it has been found that emission levels of vehicles are dependent on many parameters such as model, size and fuel type. For example, diesel exhaust contains more PM (by a factor of approximately 50-100 on a mass basis) than gasoline exhaust. The absence of any such profile on cars in the 40% category also gives a misleading picture. It is worth noting that an unexpected side effect of the earlier EU focus on controlling CO2  boosted the popularity of diesel engines, which have under the Euro 3 directive somewhat laxer standards than petrol ones.
 
The "Clean Air in London" report notes that: "the shift from petrol to diesel cars since 2000, for which Governments have been responsible, has resulted in actual primary NO2 emissions in 2010 being more than twice the level they would have been under the 2000 car fleet mix scenario (107%) - even after allowing for NO2 emissions as a fraction of NOx emissions increasing from around 5% to 20% or more in the real world;"
 
What the Jersey Environment Air Quality report does is to highlight a statistic - 40% - of vehicles for which there is (1) no automatic determination of failure to meet Euro 3 standards (2) no indication of how close vehicles are to meeting some of those standards. What would be more accurate, therefore, would be to say that 40% of cars do not automatically meet EU regulations, which is a different matter entirely.
 
Moreover, as I noted at the start, a proportion of the approximate 100,000 vehicles "on the road" are not on the road but either in garages or at homes. We don't know how many of those are at garage forecourts, or how likely those are to be sold. So we should also note that the figure is 40% of vehicles registered but not necessarily being driven around Jersey at the moment. Some may even be older collectors cars, only taken out on special occasions.
 
As these statistics are being used as a pretext for mandatory emissions testing (alongside a roadworthiness certificate), it is important that we understand their limitations. That's not to say that emissions are not important, but the figure being bandied about here is not giving the full picture. It's a good starting point, but as a tactic to introduce mandatory emission testing, it falls short.