Local air quality management: policy guidance

13. Air quality and noise

13.1 Integrating air quality and traffic noise management

Air pollution and noise are often emitted from the same sources (notably road traffic) and locations of poor air quality can coincide or overlap with locations subject to high noise levels. Even where they do not, poor air quality at one location and high noise levels at a neighbouring location may be related through the way in which traffic is managed across the wider area. In aiming for the most beneficial outcome for members of the public, it is important to seek measures that both improve air quality and reduce noise levels – for example speed restrictions – and avoid measures that worsen one while seeking to improve the other. Local authorities should ensure that an integrated approach to managing air quality and noise is taken across all departments, and when working with external partners.

13.2 Air quality action planning and noise

As stated elsewhere in this guidance, air quality action plans must include evidence that all available options have been considered in relation to cost effectiveness and feasibility.

Whenever air quality action plans prioritise measures in terms of costs and benefits, traffic noise should receive due consideration, qualitatively if not quantitatively. Special consideration should be given to noise management areas identified by the noise action plans, and any other areas where a local authority considers traffic noise to be a matter of concern, particularly where proposed air quality measures may potentially impact on noise levels.

Certain measures, particularly those concerned with reducing local traffic flows, may benefit both air quality and noise, although in some cases this may only hold true when speeds are not permitted to increase. Other potential measures that can reduce both air pollution and noise include restrictions on heavy vehicles, reducing speeds on motorways and dual carriageways, and strategies to increase the separation between the source and sensitive receptors, for example by building a bypass. However, measures to lower average speeds of traffic in urban areas, whilst usually benefitting noise, may increase air pollutant emissions. Modelling may be required to determine the optimum public health outcome for a given locality. The level of detail sought should sensibly reflect the scale of changes proposed.