SMMT 2011 CO2 Report - The Small Print

Friday 18th March, 2011
I'm sure you were made aware of the SMMT 2011 CO2 report that came out this week, along with the great news that the motor industry reduced the CO2 emissions of cars sold in 2010 compared with previous years.

But did you read the small print?

We have to go all the way to "Annex 3" on Page 39 to find the details of other pollutants, those nasty ones that affect our health like CO,NOx and PM10s. A glance at table 19 on this page shows us that all is good and these other pollutants are headed in the right direction. Or are they?

The data shown is actually from 2008, long before most manufacturers started retuning their cars for Euro 5 emissions compliance. In fact, by reference to table 18 on the SMMT report, you'll see that all this shows is the results of the successful implementation of Euro 4. Since then, we've seen extensive taxation based around CO2 and a "showroom tax" applied to the most polluting (CO2) vehicles.

But what's happened to these other pollutants since then and why aren't they shown in a 2010 emissions report compiled in 2011? In my eyes, there's no reason, the VCA clearly compiled data in 2010 just as they did in both 2008 and 2009. The claimed lack of data for other emissions since 2008 made me suspicious and led me to investigate further.

Take the Audi A3 Sportback 2.0 TDI 170ps with DPF M6 which was on sale under Euro 4 regulations. According to the corresponding VCA emissions report,  151g/km CO2, 216mg/km NOx, 230mg/km THC+NOx, 79mg/km CO

Then the car was retuned for Euro5 and became the Audi A3 Sportback 2.0 CR TDI 170PS with DPF M6. A glance at the updated VCA report shows us it now emits 139g/km CO2, a 12g reduction, the SMMT would be proud. But what happened to the other emissions?

NOx went down to 139mg from 216mg, a massive reduction of 77mg. Good news, better for health. NOx is often formed when Nitrogen, in the air, is accidentally oxidised by the highly efficient catalytic converters that modern emissions regulations demand. A reduction in NOx can actually be achieved by better tuning or...a less efficient cat. So lets look at the other pollutants.

THC+NOx is now 184mg, a 46mg reduction. Another reduction, good stuff. Or is it? We know the NOx actually dropped 77mg, so surely the THC component, those unburned hydrocarbons, have actually gone up overall. Before THC could be worked out as something like 230-216=14mg, now it's looking more like 184-139=45mg - over 3 times bigger with an increase of something like 31mg. Could it be that if you don't burn all the hydrocarbons in the fuel, dumping them out the tailpipe, that you don't generate as much CO2 and potentially get in a lower tax/VED bracket? You can ponder over that whilst we look at the choking carbon monoxide.

CO in the Euro 4 car was just 79mg. In the Euro 5 car, this is now 312mg - 4 times as much and an increase of 233mg!

Well done Audi, you appear to have inserted a LESS efficient catalytic converter, are now Euro 5 compliant, the SMMT are happy, it looks good in the report but your CO has gone through the roof as the cat appears to no longer be doing the required business. Not only all that but, despite both cars being fitted with a Diesel Particulate Filter (DPF), the newer one appears to give more PM10 particulate emissions too. Of course, if you don't burn all the carbon and leave it as soot particles, this reduces your CO2 output, so that will keep everybody happy, right?

So let's just publish the "Other emissions" data from 2008 at the back on Page 39 shall we? Maybe nobody will notice...

I contacted Paul Everitt, Chief Executive of the SMMT, before writing this article. He informed me that "the data on CO/NOx/PM10 is the latest available and illustrates the downward trend in all emissions".

This isn't just an Audi thing, they're just unfortunate enough to be the first car I looked at in the list. With many models from many different brands all having higher "other emissions" under Euro5, is it any wonder UK Air Quality is going down?

Comments/Trackbacks [7]