Noise body ICCAN recognises problems with the SoNA noise survey, and recommends new, better, regular noise surveys
One of the key surveys on attitudes to aircraft noise was the SoNA study, Survey of Noise Attitudes 2014, carried out by the CAA. The SoNA study found people were more annoyed by noise, and more sensitive to it, than another study in 1985. Some degree of annoyance and adverse effects were found down to 51dB LAeq 16hr. The conventional level of averaged noise considered a problem is 57 dB LAeq. But critics have said the study was flawed, as it only considered populations that had already experienced high levels of aviation noise, rather than communities that had been impacted for the first time, or had newly been exposed to a greater intensification of noise. With the expansion of aviation in the UK, there are many areas and hundreds of thousands of people, who are being newly exposed to plane noise. The noise body ICCAN has realised there is a problem with SoNA. It recommends that a new, regular attitudinal survey is begun before the end of 2021, and repeated frequently. And that “the new surveys should be commissioned, run and analysed independent of Government, regulators and industry. We consider it appropriate for ICCAN to take on this role, working closely with relevant stakeholders.”
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Noise data flaw
Campaigners have found that data used to calculate the impact to Survey of Noise Attitudes 2014 has been found to include inappropriate survey sampling, in a report by the newly formed Independent Commission on Civil Aviation Noise, because it had only considered populations that had already experienced high levels of aviation noise, rather than communities that had been impacted for the first time, or communities that had been exposed to a greater intensification of noise. Look out for more on this over the coming days.
“Review of the Survey of Noise Attitudes 2014”
December 2019
By ICCAN (the Independent Commission on Civil Aviation Noise)
https://iccan.gov.uk/wp-content/uploads/2019_12_18_ICCAN_Review_of_Survey_of_Noise_Attitudes.pdf
This says:
The Survey of Noise Attitudes (SoNA), conducted in 2014, is an important piece of evidence. It provided information about attitudes towards aviation noise and how they relate to aircraft noise exposure indices. This evidence was used to determine thresholds for community annoyance, which informed UK policy and guidance. It also provided data on factors that influence attitudes to aviation noise and the effects of aviation noise on health and wellbeing.
However, there has been considerable debate around the robustness of SoNA’s methodology and results, with some community groups voicing a lack of confidence in SoNA and decisions based on SoNA’s results1 .
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The aim of our review was to consider the lessons from SoNA 2014 and make recommendations on the scope of future research in this area. ICCAN spoke to a range of stakeholders and experts and reviewed relevant publicly-available documents. This report details the results of ICCAN’s review.
We have deliberately not set out to conduct a full and critical review of the methodology used, the analysis of, or the conclusions drawn from SoNA. We view our role as forward-looking and, in that spirit, we have used the evidence and knowledge drawn from this review to make achievable recommendations for the future. We view this as being of more value than simply adding to the debate and commentary on the rights and wrongs of the previous survey.
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They also say:
ICCAN’s review of SoNA provided a detailed insight into the survey itself and the issues that have been raised regarding its methodology and results. Overall, we have found that SoNA sought to follow best practice in the methodology that was used within its budgetary constraints. However, it is abundantly clear that there remain disputes over the use of the evidence base from SoNA in relation to issues such as the change effect, the ‘snapshot’ nature of the study, the sampling methodology, the lower limit of 51 dB LAeq, and its use in government policy-setting (such as the Lowest Observable Adverse Effect Level) and we have therefore identified some areas where it would be beneficial to explore how improvements to the methodology could be made for future studies. Based on this review, ICCAN has formed a set of recommendations that are set out below.
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In summary, we recommend that:
• A new, regular attitudinal survey is begun before the end of 2021, and repeated frequently.
• The new surveys should be commissioned, run and analysed independent of Government, regulators and industry. We consider it appropriate for ICCAN to take on this role, working closely with relevant stakeholders.
• ICCAN will find a sustainable and equitable solution to funding the surveys, which involves government and industry, but does not impinge of the independence of our ownership and management of the surveys.
• Improvements should be made for the new surveys using lessons learned from SoNA.
• ICCAN will run a development study to identify the best way to implement improvements for the new surveys.
ICCAN recommends that lessons learned from SoNA are used to make
improvements for the new attitudinal survey.
While SoNA sought to follow best practice in the methodology it used, ICCAN’s review
identified some areas where it would be beneficial to explore whether methodological
improvements could be made for future attitudinal surveys of aviation noise. We have
looked at some of the most significant issues in this report; however, there remain a
number of critical strategic and methodological questions that we would want to answer
before designing the new survey.
These include:
Scope of population
• How can the survey include noise contours at a level below that used in SoNA to
balance robustness of results, value for money and accuracy of lower noise
estimates? What noise level is appropriate and possible to go down to satisfactorily
examine the LOAEL and the WHO’s ‘Environmental Noise Guidelines for the
European Region (2018)’?
• Should the survey get a national view of a large number of airports or focus on
fewer airports but with increased sample coverage around them?
• How could the survey be designed to allow us to look at relevant flight operational
changes and their influence on annoyance? For example, those who are/will be
newly overflown vs. those who have been overflown for some time, those who get
respite vs. those who don’t, those who experience one mode of airport operation vs.
those who experience another (e.g. westerly vs. easterly operations).
• Should we interview one adult in each household, or should we also include
children resident in the household?
Survey mode
• Are other modes of interview feasible other than face-to-face interviewing, including
mixed modes of contact and interview?
Sampling
• What is the best way to sample to ensure the survey achieves a representative
sample of noise exposures?
• Are noise metrics the best way to achieve a representative sample for the survey or
would other strategies used in similar research (for example using distance from the
airport or flight paths) be more appropriate?
• Which noise metrics would be appropriate to use to sample, including use of
multiple noise metrics in combination?
• Which other factors that may influence responses, such as different modes of
airport operation or areas that get respite, should also be considered in order to
create a representative sample?
• Should night noise metrics be used in the sampling to ensure a representative
sample is achieved for questions on sleep disturbance?
• Is clustered sampling the best approach to use? If so, how could it be done to
ensure robust coverage of the population?
• Is disproportionate sampling needed and, if so, where?
• What sample sizes are needed to robustly conduct the analysis required?
Questionnaire
• Did the questions in the SoNA 2014 questionnaire work well or are there any
improvements that could be made?
• Can new topics of questions be developed and tested, including expanding the
sections on sleep disturbance, health, wellbeing and quality of life?
• What should the reference period for the aircraft annoyance questions be (e.g. the
summer months or 12 months previously or another period) and when should the
fieldwork be conducted (e.g. during the summer months or following them or
another period)?
• Would the survey benefit from any objective measures? For example, actual noise
measures, actual monitoring of sleep disturbance, sleep/annoyance diaries or apps,
or health monitoring.
Time series
• How can this new survey be set up to ensure that it can be conducted regularly over
time to build up a robust time series? How can the new survey contribute to the
evidence base on the change effect?
Survey costs
• What are the cost options for this new survey, in order to make an informed
decision on the survey design which balances robustness, practicality and value for
money?
Compatibility
• Should the survey seek compatibility with other historic UK noise topic surveys, or
international studies; and, if so, to what extent?
See full report at
https://iccan.gov.uk/wp-content/uploads/2019_12_18_ICCAN_Review_of_Survey_of_Noise_Attitudes.pdf
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See earlier:
CAA publishes SoNA study, showing high levels of annoyance from aircraft noise well below 57dB
On 2nd February the CAA published a report on a survey about attitudes to aircraft noise, done in 2014. It is called SoNA (Survey of Noise Attitudes). This follows the ANASE study done several years earlier, that was shelved by government, as its methodology was questioned, and it showed high levels of annoyance in response to plane noise. The SoNA study findings are that some adverse effects of plane noise annoyance can be seen to occur down to 51dB LAeq 16hr. The conventional level of averaged noise considered a problem is 57 dB LAeq, and noise is measured on a logarithmic scale. The SoNA report also found sensitivity to aircraft noise has increased, with the same percentage of people being highly annoyed at 54dB LAeq 16hr in SoNA as there was at 57dB LAeq 16hr in the ANIS study that was done in 1985. This gives further evidence to the demand that the government no longer uses the 57dB LAeq metric as its main noise measure. The debate continues about the merits of averaged noise over 16 hours in summer, with metrics measuring the number of plane noise events in a given time. The study says “there is insufficient evidence to link chronic health outcomes with event-based noise metrics, and SoNA 2014 found these performed less well than LAeq 16hr as a predictor of annoyance.” But the findings may show “it may be appropriate to use N65 as supplementary measure for daytime noise…”
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