Maybe I forgot my chenmstry. But from an emission standpoint we are concerned with CO (carbon monoxide - the killer gas) and HC (Hydrocarbons - the smog creater) but CO2 (carbon dioxide) is used in good things like carbonated soft drinks liek Coke, pellet guns and when I was much younger to drive a toy race car really fast for a short period of time & sometimes even straight.

Doubtless you know of catalytic converters, which are cheap enough but with diesel trucks you should also consider soot filters which are a cost multiple of cat converters, because of the health risk from particulates. But even then they are not entirely squeeky clean. When your trucks finally need replacing, and you still wish to remain with ic trucks, you may wish to consider CNG until something better, like hydrogen power, comes along. The great advantage of CNG over LPG is that they are much cleaner, in that they do not emit benzene, a known carcinogen. That said, there are downsides to CNG in terms of performance and other issues.

It is a pity that the green movement has taken the moral high ground over carbon emissions, based on inadequate scientific data or "bad science". We all want to see a cleaner planet but the problem is how to go about the right way to achieve that. Making pronouncements which translate into global action based on skimpy data is downright dangerous and irresponsible.

A good example is the Green movement's greatest "victory" over the bannng of CFCs, back in 1987, used mainly in refrigeration and air conditoning. It know emerges that CFCs' replacement, HFCs (hyrodflourocarbons) is far more potent, ton for ton, than carbon emissions at fouling up the atmosphere.

One ton of HFC-23 has the same global warming potential as 14,800 tons of carbon dioxide. Just how bad that news is, especially for Britons living on the west coast, you may wish to discover by going into Google and tapping in: Marine low emission zones promise longer lives.

From my experience, exhaust emissions can be measured by use of a gas analyser, but please be aware that most will provide readings in parts per million and this can be difficult to relate back to the permitted emissions under the European Stage / USA Tier standards. There are companies who will attend site to carry out this service or you can hire an analyser and conduct the test yourself.

CO2 is obviously linked to climate change and there will continue to be a deal of contentious information in the press, quite how these "green squads" will be formed remains to be seen.

In response to the main issue raised above, it is less about the tailpipe emission and more about where the truck is used; even a brand new truck used in a warehouse will eventually cause a problem where there is little or poor ventilation.

In the past, we have worked with Pyroban Envirosafe to reduce our fleet's diesel emissions for H&S reasons. Due to the nature of our business, we are unable to increase the level of ventilation needed in our warehouse so the best option for us was to use retrofit exhaust control equipment to reduce our fleet's CO, HC and smoke emissions.

As far as I know, NOx emissions can be dealt with but I believe the control system would be difficult to fit to an average FLT. Best bet would be to contact Pyroban Envirosafe

With diesel engine CO emmission have always been minimal mainly due to higher compression ratio & fuel/air ignition by compression vs. spark ignition. The main issues with diesel engines are NOX and smoke emissions.