New UK air quality targets
Air pollution is the presence of harmful substances, a blend of particles and gases in the air, posing risks to human health. These pollutants emanate from both natural processes and human activities.
Air quality consultants in the UK play a crucial role in addressing and managing the various challenges associated with air pollution.
Exposure to poor air quality has significant health implications. Love Design Studio take a science-based approach to assessing air quality impacts; using monitoring data and modelling to identify potential health risks, and inform measures to mitigate risk. This is particularly important in urban areas where the density of both the population and sources of emissions, can have a major impact on populations.
PM2.5: Out with the old in with the bold?
The Environmental Targets (Fine Particulate Matter) (England) Regulations 2023 sets two new air quality targets in response to the Environment Act 2021 which mandated long-term target setting for fine particulate matter PM2.5.
The targets are;
Annual Mean Concentration Target ('concentration target') - a maximum concentration of 10µg/m3 to be met across England by 2040
Population Exposure Reduction Target ('exposure target') - a 35% reduction in population exposure by 2040 (compared to a base year of 2018).
These targets are beginning to have a significant impact on the methodology, focus and common findings of air quality assessments (AQA’s) submitted as part of the planning process.
While PM2.5 is considered within AQAs in all relevant sections of the report (e.g. baseline conditions, background concentrations, and dispersion modelling), the previous long-term objective in the UK for PM2.5 was not fit for purpose. The objective level was previously well above a ‘safe’ concentration and was rarely exceeded in the UK, meaning it was not a material focus of AQAs. As a result of this lenient objective, operational emissions rarely had an adverse impact when assessed using industry standard methods, and more generally concentrations were largely the objective and therefore not a consideration for site-suitability .
The new annual mean PM2.5 target is more stringent than before, and current concentrations across the UK are often above the target.
Does this target go far enough?
Timeframes
Defra have been vocal about these ‘ambitious new targets’; however, how ambitious these targets are is certainly up for debate. The target year is informed by projections which indicate that the majority of the UK will meet the guideline by this year regardless of the implementation of the target. Can we consider this a target, let alone an ‘ambitious’ target, if it will be easily met? How much impact could we avoid by setting these targets for 2030, or even 2035?
Concentration Target
The target value of 10µg/m3 itself is also a source of concern. Whilst the new target is half the previous UK target for PM2.5, it is still double the guideline value World Health Organisation (WHO) have set for the pollutant (5 µg/m3). This was an opportunity for the UK to materially improve air quality, to target concentrations below levels known to lead to health issues. Surely a more stringent target would lead to quicker and more significant improvements in local air quality?
What does this mean for air quality consultancy?
With respect to AQAs , the focus on PM2.5 may lead to issues with the methodology and technical work underpinning assessment findings. Typically, assessments use dispersion modelling, supplemented by monitoring, to ascertain to air quality conditions across a development site and to assess the impacts generated by a development’s operational emissions. Dispersion modelling requires a verification process to assure the quality and robustness of results, this uses known monitored values within a domain to verify and adjust the modelled outputs. Previously, AQA’s have predominantly focussed on NO2, a pollutant that is widely monitored due to the cost effectiveness and ease of installation of monitors, it is often straightforward to verify and adjust a model based on several nearby monitoring sites; this will not be possible for PM2.5 now, nor the immediate future.
PM2.5 is both difficult and expensive to monitor accurately; therefore, there is relatively few PM2.5 monitoring stations in the UK when compared to NO2 and PM10. Whilst low-cost sensors and hyper-local air quality monitoring solutions are improving and may help resolve this, there is always risk associated with using monitors that are not suitability accredited or subject to the rigorous QA/QC processes inherent with national monitoring networks.
The exposure reduction target may also impact assessments. Population exposure reduction is only achievable if new development, and the planning system more generally, respond to the new targets accordingly and establish an appropriate methodology to assess this quantitatively. An assessment of population exposure would need extensive input and collaboration with health impact professionals, and if this target is to be responded to within AQAs, this may lead to a shift in AQAs becoming more health focussed.
