Any vans which do not meet certain European emissions criteria (named Euro 3) will be charged £100 to travel within the zone with penalties of up to £750 for late payment.
The charges apply to all vehicles registered before 1 October 2006 (with the exception of cars) and means a large number of businesses will face hefty charges in 2012.
However, van manufacturers in the LEZ are offering a series of trade-in discounts when an ineligible van is swapped for a new van.
For example, Ford is offering up to £3,000 off a new Ford Transit van and £1,500 off the smaller Ford Transit Connect.
Vauxhall has gone one better, offering up to £7,500 off a new Vauxhall Movano when an older van is traded in.
Meanwhile Renault, Peugeot, Citroen and Fiat are all offering swappage discounts on their van ranges in preparation for the charges.
“I want to make the air cleaner and greener in this great city with the minimum of financial impact for those who need to upgrade their vehicles,” says Boris Johnson, the Mayor of London, who has been instrumental in setting up the LEZ. “I’ve already given extra breathing space during the depths of the recession before these standards are introduced and I am pleased that a number of manufacturers are now offering new discounts to aid us in our efforts.”