The issue of air quality has been rising in the news of late, and its impact on planning applications is a key factor as explained by Roger Barrowcliffe, Vice Chair, Institute of Air Quality Management
Air quality has become a much more prominent topic in the media of late, featuring strongly in the London Mayoral elections and most notably being a major news story when the revelations of the Volkswagen ‘defeat devices’ emerged in September 2015. For those of us working as air quality professionals, this prominence seems rather overdue. After all, we have known for more than 20 years that air pollution in the form of fine particles is associated with a large mortality burden, equivalent to hastening the death of approximately 29,000 adults in the UK annually by about 12 years. More recently, this estimate has been increased by another 23,000 to allow for exposure to nitrogen dioxide. These are not extreme claims made by pressure groups; they are the figures endorsed by the government’s expert body and the result of careful and sober analysis. Despite this health impact making air pollution at least as significant for public health as obesity and passive smoking, if not more so, relatively little action has been taken to address the problem successfully. Many places still experience NO2 concentrations at levels above the legal limit. The government has found itself repeatedly in court defending its inability to meet the requirements of the ambient air quality Directive.
In the long term, land use planning can be a big influence on air quality. After all, our planning system determines where we live, work, shop and go to school, thereby dictating to some degree the pattern of vehicle use and the length and frequency of journeys. The air quality problem is largely an urban one and dominated by the contribution of road transport. More particularly, the current problem is perceived as one of high NO2 concentrations and a failure to meet the EU limit value for ambient concentrations of this pollutant. The spatial pattern of the problem looks very much like a road map, with highest concentrations found near the busiest roads and in city centres. Local authorities have been given responsibility for improving air quality in these locations under the 1995 Environment Act and have declared Air Quality Management Areas (AQMAs) where there is a problem meeting the legal standard for ambient air quality. The status of AQMAs is recognised in the National Planning Policy Framework, and it is understandable that planning authorities might object to any development that is seen to be adding road traffic emissions within an AQMA.
For major industrial developments or large residential developments, the presence of an AQMA makes an application far more sensitive to air quality concerns than would otherwise be the case and provides a legitimate reason for a local authority to refuse consent. The perennial problem is deciding whether any new development, of itself, would hinder the local authority’s ability to improve air quality to the point where ambient concentrations are within legal limits. Some campaign groups take a purist view and argue that any new development is incompatible with the relevant Directive in an area where the EU limit value is currently exceeded. The current arguments about the expansion of Heathrow encapsulate this view, for example.
For the vast majority of developments, the additional contribution made to NO2 concentrations is very small, amounting to the emission from the extra road traffic associated with development. The nub of the matter, therefore, is deciding whether these emissions increase local NO2 concentrations by an amount that is ‘material’ in planning terms. There is no government guidance on this or any legal definition, and so this can be a matter of fierce debate.
The Institute of Air Quality Management and Environmental Protection UK have attempted to provide all parties in the process with guidance on how and when to conduct air quality assessments. The guidance cannot answer the central question, but it does provide an assessor with a framework by which the impacts described in objective terms and suggestions as to whether this might be considered a significant effect. The guidance also urges the developer to bring forward an application that is designed to reduce air quality impacts as far as is possible.
One aspect that the planning system is not well equipped to deal with effectively is the overall impact that cumulative development brings. This is especially true of multiple residential developments in an area. Each one individually could be fairly assessed as having an insignificant effect, but the cumulative effect may be to raise NO2 concentrations in an AQMA to such a degree that the local authority’s duties to improve air quality are compromised. Unfortunately, there is no easy answer to this problem. There appears to be no adequate mechanism to oblige all the developers to quantify the combined additional contribution jointly or for the local authority to assess the cumulative impact. Since this would involve a complex dispersion modelling exercise with future traffic flow data, it is not a straightforward task for any of the parties. In many cases, the burden may fall on one particular developer, who is the last one in a chain of applications and the one deemed to be the ‘last straw’. This seems to be unsatisfactory but is an inevitable consequence of the planning system as it is currently structured.
Another topic that can sometimes present developers with a hurdle in respect of additional emissions is their effect on sensitive habitats. The Habitats Regulations place a high degree of protection on those habitats with a European level status, e.g., Special Areas of Conservation (SAC). The Regulations do not, however, define what might constitute an air quality impact that would be of relevance in planning terms, leaving the door open for considerable debate in some circumstances. In the main, the issue is one of additional nitrogen deposition from road traffic emissions using roads adjacent to, or within, the SAC. One notable case is that of the Ashdown Forest in West Sussex, which has been the subject of successive court cases following refusal of planning consent for a small housing development. Courts of law are not a satisfactory place to debate this issue, whatever their status, and the likelihood is that there will be uncertainty on what constitutes a significant effect on such habitats for the foreseeable future.
For many planning applications, air quality is not a major factor in deciding whether to grant consent. As we have seen, however, in some cases, it can be a key consideration and in these cases, there is an absence of clear and satisfactory guidance from government on how such decisions should be made. Fortunately, the current problem areas will diminish with time, as the more effective EU vehicle emission control regulations actually deliver ‘real world’ performance. Ambient NO2 concentrations are declining gradually with time and will eventually be compliant with the law in all places. This will not mean that development can ignore the need to contribute to better air quality, but it should mean that there will be fewer contentious cases where road traffic emissions are concerned.
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Roger Barrowcliffe
Vice Chair
Institute of Air Quality Management
Tel: +44 (0)20 7601 1920
info@the-ies.org
iaqm.co.uk
twitter @IAQM_UK
