Question to the Department for Transport:

To ask Her Majesty's Government what assessment they have made of the impact of diesel buses on respiratory illnesses such as (1) COVID-19, and (2) asthma; and what plans they have, if any, to ban diesel buses from (a) town, and (b) city, centres.

There is clear evidence to show that exposure to air pollution can exacerbate the effects of respiratory illnesses including asthma. Older buses, particularly those without emission abatement technology fitted, can be a significant source of emissions in some areas. National level estimates indicate that in 2019 buses contributed on average 8% of roadside NOx concentrations. However, no Government analysis has been carried out on the specific impact of buses in towns and cities on respiratory health.

Most buses in the current fleet are diesel and they form a key component of a sustainable transport package in towns and cities, with newer diesel buses emitting significantly lower levels of pollution than older models. Clean Air Zones (CAZ) are being implemented by local authorities in a number of areas where roads are exceeding legal limits for nitrogen dioxide, and all of these Zones will charge older buses to enter. Local authorities implementing CAZs have carried out local analysis to understand the key sources of pollution on their roads in order to identify the appropriate solution. In these and other local authorities engaged with the NO2 Plan, Government is supporting the upgrading of bus fleets to newer, cleaner standards either via replacement vehicles or grants to support the retrofit of older diesel buses with technologies to reduce emissions from their tailpipe.

The Government is also committed to supporting the introduction of 4,000 zero emission buses and achieving an all zero emission bus fleet. As set out in the Autumn Budget and Spending Review 2021 £355 million of new funding has been made available for zero emission buses. The Government has also committed to setting an end date for the sale of new diesel buses, further incentivising the adoption of zero emission buses.