Boris Johnson and his bee in his bonnet about diesel.

On the news recently, Boris Johnson was pushing for extra charges for diesel vehicles in the London Low Emission Zone. Apparently, nitrous oxide fumes that were once considered 'safe' are now a serious health hazard. Nitrous oxide has been around for a long time, so how much is it a genuine threat as opposed to it being milked for extra revenue?
As always, the car is the villain, but what about all the buses and heavy commercial vehicles that have diesel engines - and these are much more thirsty than the a motorcar? The possibility of other councils watching with interest was also raised.
He mentions 2020 as the date when new rules will apply, and quite casually points out that owners have plenty of time to change their vehicles. He would not stop nattering when the presenter tried to challenge him about the possibility that many diesel cars might be unsellable in the near future.

What I find laughable is the idea that a column of fumes settle over the Zone, and just sit there stationary. Yes, there probably is a temporary situation at peak times, but the UK does have wind currents, so it is possible to have either the fumes within the Zone being driven out on the breeze, or fumes coming into the Zone from farther a field, again due to being driven by the wind.