The ULEZ will be effective 24 hours a day, seven days a week, in the same area as the existing Congestion Charge zone.
All vehicles – including commercial vehicles ranging from small vans to HGVs – will need to meet the standard or pay a daily charge of £12.50 for LCVs (3.5 tonnes or less), or £100 for HGVs, buses and coaches.
Transport for London says it is taking "extra steps" to reduce bus emissions. All double-deckers, says TfL, will be hybrid by 2020, with single-deckers being zero emission (at point of use).
Vans and minibuses will need to be Euro 6 for diesel engines and Euro 4 for petrol engines. HGVs, buses and coaches will need to be Euro 6.
Mike Hawes, chief executive of the Society of Motor Manufacturers and Traders, says the London ULEZ will "set a precedent, not only in the UK but around the world".
He adds: "We are pleased to see the mayor has recognised that the latest diesel technology has a place in an Ultra Low Emissions Zone. It is only by encouraging motorists to invest in the latest, lowest emission technology, regardless of vehicle or fuel type, that the mayor's vision be fully realised."
The Freight Transport Association also welcomes the ULEZ announcement, but is calling for cross-party commitment to the current plan. It warns that businesses will face "serious difficulties" if a change of mayor leads to any alteration of the zone's geographic area or timescale.
The FTA also says smaller businesses will be impacted adversely: "FTA wants to see some help for those who will find it harder to comply as the second-hand market for Euro 6 vehicles will not have fully matured by then, and unlike previous phases of the London low emission zone, there will be no retrofit option available – essentially this means purchasing a brand new truck or van," says Natalie Chapman, FTA's head of policy for London.