Designers should measure air pollution at sites for proposed new buildings to increase the chances of gaining planning permission and maintain the health of occupants, research has concluded.
Poor air quality at regional and local level is already making the development of land challenging, according to consultancy WSP|Parsons Brinckerhoff.
As the issue has moved up the political agenda, the consultancy has noted an increasing trend for local planning authorities to demand more information on the impact of a new development on local air quality.
Developers need to take the issue into account when selecting sites and consider the impacts appropriately to achieve planning permission, the consultancy said. levels of nitrogen dioxide (NO2) and PM10 already breach of legal limits in more than 600 locations within UK local authority areas, the consultants said.
These locations are likely to be subject to extra rules to minimise further air pollution.As the main source of city air pollution is from vehicles at ground level, models tend to predict a rapid improvement in air quality with height. However, little monitoring has been undertaken to verify this assumption.
Air quality specialists at the consultancy measured NO2 concentrations at different heights at 26 locations in London and Cardiff. Although the results showed that air quality at roadside locations improved up to the fourth floor of buildings, further improvement beyond that was minimal.
In some cases, typically away from main roads, the research found that air pollution concentrations were relatively constant with height.
Street canyons, where buildings of several storeys high are found on both sides of the road, can worsen air quality by limiting dispersion of pollutants, WSP|Parsons Brinckerhoff found.
The consultancy outlined five recommendations for building designers and developers:
- Consider air quality at an early stage. A site-specific air quality appraisal should form part of the environmental due diligence process.
- Take care when locating air intake equipment. Air intakes should ideally be located on non-road facing façades or in elevated positions to avoid emissions from vehicles and other sources.
- Centralised energy facilities or renewable energy sources should, as a minimum, meet the standards for nitrogen oxide (NOX) emissions in planning guidance from the Greater London Authority, unless the local planning authority has its own requirements.
- Be aware of developments in a street canyon, or that introduce a new canyon. Technical expertise is required in such cases.
- Ensure sufficient evidence is presented with a planning application to minimise the requirement for mitigation, such as NOX filtration, which has ongoing maintenance costs.
Last week, the government received a final warning from the European Commission over its failure to tackle air quality. It must publish a new air quality strategy by the end of April to avoid legal action.
Exposure to air pollution causes around 40,000 deaths in the UK each year, according to research published last year by the Royal College of Physicians.
