Memorandum submitted by TRL (AQ 22)


TRL is a leading research and consultancy organisation, with wide-ranging experience in the environmental impacts of transport. TRL has worked in the field of air quality for more than 40 years. We have over 50 staff in our Centre for Sustainability, of which some 13 staff are professional researchers in the fields of emissions and air quality. We have a comprehensive understanding of the relationships between transport policies and emissions, and have been pivotal to the development of a number of modelling tools for different transport modes. TRL was responsible for the recent revision to the UK road transport emission factors, as published by the DfT. In addition TRL developed and has operated since the early 1990s, the Highways Agency roadside air pollution monitoring network. Therefore one of TRL's key research themes is the relationship between transport emissions and air quality. Typically, TRL operates a network of approximately 30 continuous air pollution monitoring stations, for a range of local authorities, engineering consultancies and central government clients.


TRL is therefore well placed to provide a view on the various questions raised in this consultation. Our responses to each of the key questions, is provided in the following sections. TRL would be happy to expand on any of these points, if they are of interest to the Committee.


Question 1: Monitoring and modelling systems used by the Government and whether these provide an adequate measure of air quality.


There are two main reasons to monitor and model air quality. One is for compliance with EU limit values (and AQS objectives) and the second is to understand the exposure of individuals and environments to air pollutants. The existing UK monitoring facilities are well established to monitoring against air quality standards, but are poorly designed to measure local conditions and human exposure.


The monitoring and modelling undertaken within the UK is widely acknowledged as being exemplary. However the monitoring network is based on high precision monitoring techniques which are relatively high maintenance. The additional emphasis on an extensive QA/QC also adds considerable costs to the operation of this network. Whilst those sites used in reporting air quality limit value compliance to the EU must meet specific minimum standards, it is arguable if this high cost approach is really required for all monitoring situations.


The choice of TEOMs for use in the measurement of particulate matter indicated that Defra failed to appreciate the composition of ambient particulate matter, and the impact of this composition on this measurement technique. This was surprising. The results from the early equivalence trials were not widely disseminated to the air pollution community, and this reluctance to be transparent is to the detriment of Defra. In addition the development of the 'correction tool' for TEOM data (VCM) was undertaken with limited consultation and third party scrutiny. Given the importance of confirming an appropriate measurement technique for PM, it would have been appropriate to consult on the use of the VCM model and the adoption of the FDM-TEOM measurement system.


Defra must be praised for the wide dissemination of the monitoring data from its networks. This enables additional data scrutiny and analysis by third parties. However, whilst funding is made available for monitoring (equipment and calibration), insufficient time and resources are made available for the analysis of data. The emphasis on measurement rather than data analysis should be addressed. This lack of data analysis limits the value of these data.


To better understand air pollution data, it would be better to integrate these measurements with the measurement of local traffic (flows, speeds and composition) and meteorological conditions.


In many cases monitoring data are extracted as the 'source increment'. This process requires the identification of suitable background sites. However, the Defra network was not established to allow this type of paired-site analysis.


It is not surprising that the TEOM method has now failed its equivalence testing against the European reference method. The robustness of the VCM correction method is questioned.


The modelling of air quality is widely undertaken in the UK, and forms a key component of the local air quality management system. The modelling is undertaken at two levels-the derivation of background concentrations, and the modelling of superimposed sources using models such as ADMS. Crucial to the estimation of pollution concentrations is the appropriate estimation of background concentrations. Within the UK, this area is dominated by the mechanistic model developed by AEA. These types of models are good for existing and historic situations, but are less reliable for the prediction of future conditions. This remains a weakness in the UK air pollution modelling.


The link between the control of local air pollutants and CO2 remains poor.


The existing monitoring and modelling fails to identify local level air pollution hotspots.


Question 2: The extent to which the Government fully understands and has identified the health and environmental risks caused by poor air quality.


During the 1950s, the UK were at the forefront of research into the relationship between air pollution and health. However no one government department takes responsibility for this issue, and this results in unnecessary confusion. However the work of COMEAP must be praised as a body that brings together knowledge in this sector. However, the chair of COMEAP has once again stated that there is no justification for health effects associated with NO2, at ambient concentrations encountered in the UK. Given that the reduction in NO2 concentrations has been central to the Government's local air quality management process, it does call into question if these activities have offered the best value for money. A strategy that focuses on PM concentration reduction would have had a more beneficial impact on health protection.


The Government claims to be seeking ways of reducing the public exposure to air pollutants, but it is unclear if they understand what this means. Large scale dosimeter measurements are not undertaken. The measurement of ambient air quality provides little information on human exposure.


Question 3: The extent to which the delivery chain for air quality is coherent, integrated, coordinated and effective and whether the bodies with responsibility for managing air quality have appropriate incentives, understand their role and responsibilities, and are adequately resourced.


Air quality management in the UK is cascaded to the local authority sector. Whilst guidance and funding is available from Defra to support this process, the cascade of this responsibility is not the most efficient way to establish consistency in the derivation of compliance with standards/objectives and air quality trends.


In many cases local authorities have limited knowledge and skill sets, and more importantly involve pollutants and processes over which they have little control. This is particularly the case for O3, and the background concentrations of PM and NOX. The provision of technical help desks appears to be a good approach, but is restricted by the limited number of experts an organisations involved in the provision of advice. The involvement of professional organisations such as IAQM should be encouraged, rather than the current reliance on single Defra consultants.


The local air quality management process focuses on procedures, rather than understanding.


Local authorities are responsible for the development of air quality action plans. However, these action plans are often poorly funded, and lack monitoring to ascertain their real benefits to local air quality.


Coordination of air pollution responsibilities between government departments, Defra, HPA, DfT and agencies such as the Highways Agency and the Environment Agency appears poor and lacks an integrated approach.


The greater participation from the regional authorities is recommended. The role of AQEG has been influential in the consensus on air pollution monitoring and modelling. However, whilst the regional authorities are party to groups such as AQEG, they failed to actively participate.


Question 4: The steps that need to be taken to ensure that air quality targets will be met in the future.


We would like to propose the following:

- More work on source apportionment.

- A wider appreciation on non-exhaust PM emissions.

- An improved integration of the research agenda with the Research Councils.

- More active engagement with the wider research community. Advice to Defra is dominated by a few suppliers which can limit the wider consideration of views.

- The further use of instantaneous emission modelling is recommended.

- To limit the turnover of staff in the air quality division of Defra. The majority of staff are relatively new to the discipline. In the event that the long term and stable lead by Martin Williams changes, then the skills of the department must be questioned.

- A greater role for the Environment Agency in the monitoring of UK air quality.

- An investigation of the decoupling of the downward trends in estimated emissions and the response in roadside air pollution concentrations.

- An assessment of the performance and successes of the roll out of air quality action plans.


14 December 2009