However, Mayorâ€™s Office says upgrading New Routemaster buses to Euro VI is not the best way of boosting Londonâ€™s air quality
New Routemaster buses will be â€œLondonâ€™s dirtiest, most polluting busesâ€ from 2020 and exempting them from the proposed ultra low emission zone (ULEZ) from is â€œindefensibleâ€, according to a London Assembly Member Stephen Knight.
After questioning by the London Assembly, the London Mayor has revealed that 306 New Routemaster buses â€“ which meet Euro V air quality emission standards â€“ will be exempt from travelling within the proposed ULEZ from 2020, despite all other London buses being required to meet more stringent Euro VI emission standards.
And, Lib Dem Mr Knight claims that under current pants, this will make the New Routemasters Londonâ€™s most polluting buses from 2020, despite only having been operating on the capitalâ€™s streets since 2012.
Other double decker buses in central London after 2020 will be either Euro VI compliant diesel-electric hybrid vehicles or will have been retrofitted to meet Euro VI emission standards for nitrogen oxides.
Mr Knight criticised the Mayor, Boris Johnson, as he said the Routemasters will remain on Londonâ€™s streets â€œfor years to comeâ€ while emitting five times more nitrogen dioxide than other buses in central London from 2020.
He said: â€œAllowing the New Routemaster to be exempted from the pollution standards in the proposed ULEZ is completely indefensible. This double standard is the price of his irrational obsession with the incredibly expensive New Routemaster bus, when his first priority should be to protect the health of Londoners.
â€œThe Mayor of London should have taken a real lead by putting zero exhaust emission electric buses on our roads long ago, but over the last six years has failed to do so.â€
However, a spokesman for the London Mayor said that after 2020 more than 90% of the buses in the ULEZ will be Euro VI standard and that the Euro V New Routemaster bus was â€œby far the greenest bus of its generation and is already substantially reducing CO2 and NOx emissions in the capitalâ€.
According to the Mayorâ€™s Office, the Euro V New Routemasters are also â€œclose to the Euro VI standardâ€ as they offer a reduction of 80% in NOx emissions on the fleet average compared to a 95% for Euro VI buses.
In addition, it would cost Â£15 million to upgrade the New Routemaster buses to Euro VI standard, which would not have such a positive impact on Londonâ€™s air quality compared to Transport for London (TfL)â€™s chosen option of upgrading Euro III standard buses, the Mayorâ€™s Office said.
The spokesman explained that TfLâ€™s chosen strategy of upgrading Euro III buses freed up resources to remove higher emission vehicles from the capital sooner in order to bring about a â€œmore rapid change in air qualityâ€.
The spokesman for the Mayor said: â€œGiven that upgrading the remaining Euro V buses to Euro VI would cost up to Â£15m yet only reduce NOx emissions in the zone by one percent, TfL has decided the most effective way of improving air quality across the whole of London would be to use those funds on schemes like replacing the far more polluting Euro III buses that operate outside the zone.â€