Representation by UK Health Security Agency (UK Health Security Agency)
- Date submitted
- 20 October 2023
- Submitted by
- Other statutory consultees
Thank you for your consultation regarding the above development. The UK Health Security Agency (UKHSA) welcomes the opportunity to comment on your proposals at this stage of the project. Please note that we request views from the Office for Health Improvement and Disparities (OHID) and the response provided is sent on behalf of both UKHSA and OHID. We can confirm that: Environmental Public Health Air Quality UKHSA is pleased to note that the applicant has included the PM2.5 commitment detailed in the Department for Environment, Food and Rural Affair’s (DEFRA) Environmental Improvement Plan 2023. The applicant reports that “The largest change in annual mean PM2.5 concentrations due to the Project in 2029 is predicted to be 0.1 ?g/m3, for example at receptor R_411 located at Ashcombe Road which has the largest With Project total of 13.0 ?g/m3. These changes would relate to negligible impacts at all human receptors due to the Project for PM2.5 concentrations and therefore no significant effects are anticipated.” UKHSA notes that Table 13.5.3 of the Air Quality Chapter details the assessment matrix for long-term concentrations. The increase identified above is between 103-108% of the Air Quality Standard and the percentage change in concentration is 1%; therefore, this equates to a moderate impact in line with the applicant’s matrix. This is not detailed in the assessment text highlighted above and UKHSA recommends that this is clarified by the applicant. Noise This response looks specifically at whether the information provided adequately captures and presents the health effects attributable to noise from the proposed development (the Scheme), thereby enabling the decision makers to make informed decisions. UKHSA welcomes: • The presentation of population exposure to noise in several different formats and metrics – both in absolute terms and as change with and without the project – for a central case and a slower transition to quieter aircraft. • The Applicant’s acknowledgement of the strong link between transport noise and adverse health outcomes (for example 18.8.96), and the acknowledgement that noise effects can be considered to have non-threshold effects (18.8.98). • The detailed consideration of noise in the Health and Wellbeing Chapter (5.1 Ch.18) (including reiterating key conclusions from the noise chapter) • The consideration of recent scientific evidence on the health effects of noise (Appendix 18.4.1). The Applicant has chosen to present the quantitative health impact assessment of noise effects (Table 18.8.24 and Appendix 18.8.1) solely as the difference with and without the Scheme. UKHSA would have preferred if the health effects of a future expanded Gatwick were also presented in absolute terms. UKHSA also encourages the Applicant to present the number of people estimated to be highly annoyed and highly sleep disturbed (in addition to the associated monetary values shown in Table 14.12.2). Given current uncertainties in the exposure response relationships (ERRs) for these two health endpoints, UKHSA recommends that sensitivity analyses are carried out for these estimates (e.g. using ERRs from the 2018 WHO Noise Guidelines). UKHSA welcomes the WebTAG assessment (Table 14.12.2). The Applicant is encouraged to provide more detail about the significance of these values in Chapter 14 and Chapter 18, and to acknowledge that this assessment was based on scientific evidence that is approximately 20 years old. UKHSA cautiously welcomes the awakenings due to noise assessment, but has reservations on how the narrative and results have been presented. For example, paragraph 18.8.177 references a quote by Basner et al. (2006): “On average there should be less than one additional awakening induced by aircraft noise”. The word “additional” in that paper was meant to refer to awakenings in addition to spontaneous awakenings that happen naturally during the night. However, the Applicant has chosen to use the word “additional” to refer to additional awakenings over and above spontaneous awakenings and awakenings that would take place due to noise from a future Gatwick without the Scheme. In UKHSA’s view, the way the results were presented (change in awakenings with and without Scheme averaged over a large population) is not in line with the assessment proposed by Basner et al. in the same paper . UKHSA encourages the Applicant to consider replicating the approach taken in that paper, were contours of one, two and three additional awakenings due to the total noise from a future year Gatwick are generated and presented. These can then be compared with the contours that are informing the project’s Noise Insulation Scheme. The Applicant is also encouraged to clarify and/or correct the statement in 14.4.51 that “N60 night gives an indication of the number of aircraft noise events on an average summer night that are above peak noise levels that might begin to cause disturbance to sleep indoors with windows open”. Referring to Figure 6 in the Basner & McGuire paper used by the Applicant to carry out the awakening assessment, and assuming an outdoor to indoor sound level difference of 10dB for open windows, N50 (outside) would have been a more appropriate metric to capture the majority of aircraft events that might cause disturbance to sleep. UKHSA notes the reference to the Department for Transport (2017) publication for the setting of a LOAEL of 51dB LAeq,16hr for air noise. As noted in 14.2.52, the SONA study found that 7% of the sampled population living around UK airports in 2014 were highly annoyed at this level. This should have been acknowledged in the Health and Wellbeing chapter, together with recognition that the chosen LOAEL for the Scheme is not likely to protect more vulnerable subgroups, including those that are highly noise sensitive. In 14.4.66 the Applicant has expressed their choice for an air noise SOAEL (63dB LAEq,16hr) in terms of the percentage of the population highly annoyed at this level according to the SONA 2014 survey. UKHSA encourages the Applicant to also indicate the estimated increased risk at this level for stroke, IHD and depression, based on the evidence in Table 3.3.2 in Appendix 18.4.1. On noise envelopes, 14.9.185 states that “The LOAEL contours have been chosen because they represent the lowest level of observable effects during the day and night…” This statement contradicts paragraph 14.2.52 and the growing body of evidence suggesting that adverse effects occur below 51dB LAeq,16hr. UKHSA encourages the Applicant to continue engaging with local stakeholders to define a noise envelope that best meets their needs. On the topic of forecast noise levels (14.9.198), it may also be useful for the Applicant to commit to looking retrospectively and checking the accuracy of previous forecasts, which could help improve the level of confidence and trust in this initiative amongst community groups. In Section 14.2 the Applicant points to legal precedent to argue that noise insulation addresses policy requirements. UKHSA welcomes noise insulation as a last resort mitigation measure. However, the Applicant should be transparent on the many limitations of such a mitigation measure, and on the significant uncertainties whether noise insulation will mitigate the adverse effects identified. Such a discussion would be particularly relevant to Chapter 18. For many decades large infrastructure projects in the UK have specified noise insulation measures as a mitigation measure, however none of them have evaluated their effectiveness to protect health. As a result, we have very little good quality evidence to confirm whether sound insulation schemes are effective to protect health, and the extent of unintended consequences. For example, sound insulation may reduce indoor noise levels at the expense of poorer indoor air quality and increased risk of overheating. In the consideration of changes to the assessment because of climate change, the Applicant states that “changes in climate could increase heatwave in the summer months…The proposed enhanced NIS for homes within the forecast 54 dB LAeq,16hr daytime air noise contour includes acoustic ventilators to allow residents to keep windows closed.” How confident is the Applicant that current technology of acoustic ventilators can provide sufficient airflow to cool a building in a heatwave, whilst also ensuring sufficient attenuation to noise ingress from outside? Under the subheading of “Thresholds and non-threshold effects”, 18.8.112 states that “The number of people experiencing noise effects at or above the SOAEL is a guide for the health assessment as to the potential for health effects within a population.” UKSHA does not agree with this statement. A health assessment should consider all adverse effects above the level where adverse effects are known to occur. By definition, this is the LOAEL not the SOAEL. Indeed, the concept of a SOAEL does not exist in conventional health risk assessment. The same paragraph also states that “the great majority of changes are no greater than 2dB, which suggests that the additional noise would not be noticed by most people and would have limited potential to affect population health.” The “rule of thumb” that a change of 3dB is barely noticeable is questionable, and many would argue that it is not applicable to an intermittent source such as aviation noise. An increase of 2dB is roughly equivalent to a 60% increase in the number of flyovers (everything else being equal), and it is debatable whether such an increase “would not be noticed by most people”. The extent to which such an increase affects population health will depend on several factors, including the existing level of exposure, the current state of health of that population, and other contextual factors (as indeed stated in Chapter 18). Paragraph 18.8.225 states that the only monitoring the Applicant is committed to carry out is Flight Performance reports, annual Noise Contour Reports, and annual reporting against the Noise Envelope limits. Given the uncertainties associated with flightpaths, fleet transitions, the main mitigation strategy (noise insulation), and the ineffectiveness of this mitigation on noise exposure outdoors, UKHSA recommends a commitment for monitoring: A) the effectiveness of sound insulation to deliver healthy indoor environments and reduce noise-induced awakenings in practice (taking into account real-life ventilation practices); and B) annoyance and self-reported sleep disturbance in the community at discrete milestones throughout the project’s construction and operation phases. UKHSA would be happy to discuss with the Applicant how this can be delivered in a proportionate way to the scale of negative environmental impacts and the predicted economic benefits. Additional Noise comments • 14.4.86 mentions a mental health facility, however it is not clear how effects on this facility have been judged and, if necessary, mitigated. • Table 14.4.2 states that consideration of Quiet Areas has been scoped out – this seems odd given the geographical area where Gatwick is situated and the spatial extent of the noise assessment. Can the Applicant clarify if or to what degree stakeholder engagement (including local communities) influenced this decision? • It is not clear if future people living in the different “Tiers” of proposed future development identified in the Cumulative Effects section of Chapter 14 are included in the population exposure to noise tables in Chapters 14 and 18. • 18.8.94 states that BS 5228-1:2009 and BS4142:2014 set out “Regulatory thresholds for health protection”. The Applicant should clarify that these standards are based on professional judgement, and are not based on any recent epidemiological evidence. • In 18.8.97, the Applicant should acknowledge that whilst SoNA 2014 failed to find associations between aircraft noise and self-reported health, it did find associations between noise annoyance and self-reported health. This is consistent with several other international studies . • In 18.8.102, the Applicant should correct the statement about noise complaints – the PHOF indicator B14a represents the rate of complaints to local authorities on neighbour and neighbourhood issues, and has no relevance to transportation noise. • It would have been helpful if the population exposure tables in Chapter 18 were presented in terms of Lden, which is the metric used in most of the epidemiological evidence on the health effects of noise. It would also be helpful if the Applicant clarifies what metric was used for the analysis described in Appendix 18.4.1. • 18.8.130 seems to suggest that the Applicant is certain that noise insulation will reduce adverse health outcomes. The Applicant should provide details of which epidemiological evidence they are basing this assumption on. • UKHSA has assumed that all noise metrics are A-weighted, it would have been good if the acoustic metric notation made this explicit rather than implicit. • Chapter 14 of the ES (14.2.3) refers to best practicable means (BPM) to control noise and vibration from construction. BPM is a legal defence against enforcement action for nuisance, such as noise. Health effects can still occur even when BPM is achieved. Following our review of the submitted documentation we are satisfied that the proposed development should not result in any significant adverse impact on public health. On that basis, we have no additional comments to make at this stage and can confirm that we have chosen NOT to register an interest with the Planning Inspectorate on this occasion. Please do not hesitate to contact us if you have any questions or concerns. Yours sincerely, On behalf of UK Health Security Agency nsipconsultations@ukhsa.gov.uk Please mark any correspondence for the attention of National Infrastructure Planning Administration.