Air Quality Technical Report - Q and A
Q. What is the purpose of the report?
A. The report sets out the recommended methodology for assessing air quality at Heathrow. These assessments will enable us to determine whether 'mixed mode' and/or the addition of a third runway are possible within the strict air quality limits set out in the Air Transport White Paper. The report does not make any conclusions about the likelihood of meeting these air quality targets.
Q. What happens next?
A. Air quality at Heathrow will now be reassessed using this methodology. We expect to consult on options for mixed mode and a third runway in 2007.
Building on the recommendations in the report, the DfT is now running the selected air quality models, using the outputs from modelling of surface access scenarios.
Q. Why was this report necessary?
A. Previous work in this area was felt to be insufficient. Government therefore established a programme of work in spring 2004 to review the way in which air quality around Heathrow should be reassessed.
Q. What was wrong with the previous methodology?
A. Earlier technical work noted that there were problems related to representing background emissions, future aircraft operations, initial dispersion of aircraft plumes and future trends in the effects of nitrogen oxides and primary nitrogen dioxide. Previous technical work was relative, not absolute, and hence the emissions inventory uncertainty was large in some areas. These issues have been addressed in the technical panel report.
Q. How has it been verified?
A. The air quality report represents the outcome of a comprehensive technical review over the past two years, involving scientific and technical experts in the field including representatives from universities, the Department for Environment, Food and Rural Affairs, local authorities and the aviation industry. Panel activity has been peer reviewed (list of participants available on our website) and cleared as unbiased, fair and technically sound. The peer review panel, comprising independent reviewers, was established in line with practice recommended by the Office of the Commissioner for Public Appointments (OCPA).
Q. How will you ensure that you satisfy you own criteria of 'being confident that air quality limits will be met' before approving further development?
A. The technical process has been designed to give us the best possible means of estimating future emissions. We will have to take account of remaining uncertainties, for example by suitable sensitivity testing and [where necessary] adopt a cautionary approach.
Q. Are you not just trying to change the methodology to get the answer you require?
A. No. This review and report has been a necessary step to address uncertainties acknowledged at the time of the White Paper and to enable us to proceed to the next stage of inventory construction and scenario modelling. Furthermore, it has been independently peer reviewed and cleared as unbiased, fair and technically sound.
Q. What are the main pollutants at Heathrow?
A. Nitrogen Oxides (NOx), nitrogen dioxide (NO2), particulate matter (PM10) and ozone (O3).
Q. What impact does this report have on meeting the EU limit on nitrogen dioxide emissions by 2010?
A. It is well known that EU limit values are currently being breached in the immediate vicinity of Heathrow and adjacent to the M4, M4 spur and the A4 (and the report confirmed this). The potential for introducing mixed mode operations and/or a third runway are subject to our being able to show that levels of NO2 emissions at Heathrow can be managed within the EU limit as soon as possible. EU negotiations are underway on a new Ambient Air Quality Directive, if agreed, it will contain the possibility for Member States to postpone compliance with the EU limit values for NO2 for up to five years providing that a comprehensive action plan is produced and submitted for approval.
Even if agreed, the UK will need to bring these areas within compliance with the limit values by 2015 at the latest.
Q. How many monitoring stations were used in the study and where are they located?
A. The details are in the full report at paragraphs 2.40 - 2.47. Monitoring sites were selected in order to adequately describe the existing pollution climate, which was to be considered in four basic contexts: concentrations near to roads, concentrations near to the airport, local background concentrations and regional background concentrations. It was also recognised that particular attention would need to be paid to the area to the northeast of the airport, due to the prevailing south-westerly winds.
There were 18 monitoring sites in total. Of this number, 2 sites breached the N02 limit in 2004. The location of these sites was LHR2 (to the north of the airport within the perimeter fence) and LHR16 (alongside the M4, west of Junction 4 (West Drayton).
Q. What are the key findings of the report on emission levels?
A.
- Confirmation that the EU limit values for N02 were breached at a number of sites around Heathrow in 2002 and 2004
- The overall trend for NOx is improving but the reduction in NO2 is considerably less marked.
- The EU limit value for PM10 which applies from 2005 did not show any exceedences at any sites.
- There are no other pollutants at Heathrow that are of significant concern.
Q. I live near Heathrow - should I be worried?
A. The main air pollution issue around Heathrow relates to the long-term limit value for nitrogen dioxide. This is based on the fact that there is some evidence for a long-term effect of nitrogen dioxide on respiratory symptoms in children and for a small effect on lung function in adults and children. There is uncertainty over whether the effect is due to nitrogen dioxide itself or to some other pollutant (pollutants often occur together so it can be difficult to separate their effects). It is important to take a precautionary approach but nitrogen dioxide is considered to have a less severe effect on health than either particles or ozone.
Q. What are the key recommendations of the report?
A.
- Recommended use of a particular air quality model for future assessments
- Detailed recommendations relating to the way emissions should be assessed now and in future (up to 2030)
Q. How much did the report cost and who paid for it?
A. The technical panel work up to mid 2006 cost around £700,000. The panels and the peer review process have been funded from within the Department for Transport's programme budget. Funding is in place to carry out the air quality modelling, reflecting the recommendations of this report.
Q. How much worse would air pollution be with a third runway?
A. A third runway could lead to an increase in annual air transport movements (ATMs) from 480,000 to around 655,000 or more. Whilst this would be highly advantageous for the UK economy, it would bring with it environmental implications, regarding noise and air quality. That is why the Air Transport White Paper makes it quite clear that we will only proceed with a third runway if we can be confident that the key condition relating to compliance with air quality limits can be met. We will not know this until we have carried out the necessary modelling work, building on this report.
Q. What does this all mean for the prospects for a third runway (and/or mixed mode) at Heathrow?
A. It is too early to say. Application of the Panel's recommendations should enable us to conduct a more robust assessment of Heathrow's future air quality, but it is not until the methodology has been put in place and the air quality modelling carried out, that we will know whether a third runway and/or mixed mode is more or less likely.
Q. When will the modelling be completed?
A. Further modelling will be carried out in the coming months. We expect to go out to public consultation in 2007, with policy decisions expected around the end of that year.
Q. Where can I get a copy of the report?
A. The full technical report (300 pages) is available on our website as is the executive summary. Notes of the panel meetings have been published on the DfT website throughout the process.
