Mulling all this over, an idea began to take shape.
My dad and I had two very interesting cars. The kind of cars that would be held up as just the kind we should be scrapping.
Why not test my ageing petrol Golf against dad’s newer Skoda Octavia diesel?
It would be Top Trumps – but for emissions rather than 0-60 in 3.8 seconds.
I was hoping our two cars would tell us something about the existing stock of cars on the road.
My dad’s car was made in 2009, so it’s eight years old, the average age of a car in the UK.
Mine, at 23 years old, is a senior citizen. But that too would tell us something about petrol engines from the distant past and how they age.
Despite the outcry about air quality, no-one really knows how to frame the problem.
Is it all to do with the type of engine – diesel v petrol? Is it the age of the engine – are old bangers the problem? Or is it about the manufacturer – are some makes better than others?
And then what about NOx and particulates – are some good on one and poor on the other?
And where does that leave carbon dioxide emissions, the greenhouse gas now rather forgotten in our focus on the more immediate peril of particulates and NOx?
In late July the government published its air quality plan – after being compelled to by the High Court. The document put the onus on local authorities to enforce controls where limits on NOx were being exceeded.
Highly polluting vehicles could be charged or banned from certain areas. A car scrappage scheme was not in the plan but neither was it ruled out.
London has already jumped the gun with its T Charge, to begin on 23 October, which will charge drivers of pre-2005 cars (Euro 1, 2 or 3 in the jargon) an extra £10 to enter the congestion zone, regardless of whether their car is petrol or diesel.
It is a precursor to the much more ambitious Ultra Low Emission Zone, penalising any vehicle made before autumn 2009 (pre-Euro 5) – which now seems likely to come into force in 2019 and to cover a large area between the North and South Circular ring roads.
In other words, local government is coming for you. But are they going after the right targets?