Aviation night noise effects (ANNE) study FAQs

General

1. What is this research about? More specifically, what is the research question?

This research study is about the impact of aviation noise at night on sleep and annoyance. The study is seeking to answer the following research question: ‘What is the relationship between exposure to night-time aviation noise and sleep disturbance and annoyance, and how does this relationship vary by different times of night?’

2. Why is DfT leading this research?

The Department for Transport’s (DfT) Transport Analysis Guidance (TAG) provides appraisal values that can be used to understand the impact that exposure to aviation noise has on annoyance, risk of acute myocardial infarction (AMI), stroke, dementia and sleep disturbance[1]. However, this uses exposure-response functions that are not specific to night-time aviation noise. Recent literature suggests the impacts of exposure to aviation noise during the night-time can differ to that experienced during the day.

Exposure to aviation noise at night can impact on physical and mental well-being[2]. Humans continue to respond to sounds in the environment even when asleep, which can cause awakenings and poor sleep quality[3] [4]. This sleep disturbance can have a negative impact on health, increasing the risk of daytime sleepiness, hypertension, and cardiovascular disease[5].

The DfT recognises this evidence gap and is undertaking this research to derive exposure-response functions between night-time aviation noise metrics and sleep and annoyance outcomes. This could be used to support the ongoing reviewing of night-time aviation policy, to inform the DfT’s future policies for night-time aviation noise exposure and assist with the management and mitigation of health impacts on local communities, as part of a wider assessment of the costs and benefits of night flying.

3. Who is funding this research?

The Department for Transport (DfT) recognises this is an evidence gap that needs to be filled in order to support important policy decisions on aviation noise. The DfT has therefore taken on the responsibility of undertaking this multi-year research project and is fully funding the project.

Participation

1. I have not received my invitation to participate as yet. How can I participate in the research?

Addresses have been chosen at random to make sure that we get a truly representative picture. This will ensure everyone has an equal chance of being selected and there is no bias in terms of how the sample of survey respondents were selected. The addresses that have been chosen will have received a letter in the post inviting up to two adults in their household to take part in the research. Addresses can’t be replaced by anyone else because this would bias the results, so only those who have been invited can participate. If you receive a letter about taking part in the research, please do not share this with anyone outside of your household.

2. What will I receive in return for my participation?

Those who have been invited and fully complete the questionnaire will receive a £10 Love2Shop voucher which can be used at a range of high street shops. It can be received as either an email or in the post, depending on the participants’ choice. Participants need to complete the questionnaire in its entirety to be eligible for receiving the voucher.

3. What if I change my mind about participating, can I opt out once I complete the questionnaire?

Yes, if someone completes the questionnaire and changes their mind later on, they can request to have their data deleted by contacting NatCen Social Research. The contact details can be found on the invitation letter, and also below:

Freephone: 0800 652 4570
Email: annesurvey@natcen.ac.uk

If you have received a letter about taking part in the research, you can read more about the survey and what taking part involves on this website: www.natcen.ac.uk/annesurvey

Research approach and techniques

1. What is the research study design?

The project team has a wide range of experience to draw on in order to answer the research question. The study has been designed as two phases:

Phase One will be a large-scale cross-sectional survey carried out among residents living near eight UK airports to assess associations of aircraft noise exposure at night and subjective sleep disturbance and annoyance.
Phase Two will recruit a sub-sample from the cross-sectional survey into an objective sleep disturbance study, where physiological assessments of (objective) sleep disturbance will be linked to aircraft noise exposure at the participant’s home. The question of differences in impacts of aviation noise on sleep disturbance at different times of the night can only be addressed using measures of objective sleep disturbance where aviation noise during specific time-periods can be linked to objective physiological reactions (e.g., awakenings).

The cross-sectional survey (Phase One) will ask respondents to think about the “summer” period (defined as mid-June to mid-September 2022). We will model aircraft noise exposure levels at each address where a survey has been completed. The models are computerised versions of the airport operations that occurred over the summer period. They are used to calculate the level of noise from the operations. A model for each airport will be included in the study. Validation work of the model will be undertaken for each airport utilising L_Amax and SEL (Sound Exposure Level) event levels captured from each airport’s noise monitoring terminals. This is to ensure that the noise model broadly reflects measured noise levels.

The survey will take approximately 20 minutes to complete. The survey is using established and standardised questions, where available, with questions selected to align with those used in SoNA 2014 (Survey of Noise Attitudes), previous UK national noise surveys and the FAA's (Federal Aviation Authority, USA) National Sleep Study to ensure continuity and comparability where possible.

The objective sleep disturbance study (Phase Two) will be undertaken later in 2023-2025.

2. Have you tested this research approach?

Yes, a pilot study of the cross-sectional survey was conducted in July 2022 to test the research approach. The overall aims of the pilot study were to test the survey procedures and questions. Acceptability of the objective sleep study was also tested through the use of a consent question in the cross-sectional subjective survey. A feasibility study of the objective sleep study is going to take place from Winter 2022 to Spring 2023. This will recruit a sub-sample from the cross-sectional survey and will test the study methodology and analysis, ahead of the main objective study later on in 2023.

3. Why have you decided to use a Push to Web survey approach?

Push-to-web methodology involves writing to a random sample of addresses and asking the residents to take part in an online survey by typing the survey URL into their address browser. They also receive a unique access code to enter the online survey. This methodology is increasingly used on social surveys[6] (for example, the Census 2021 was conducted as push-to-web first for the majority of households) and enables a large sample to be reached, whilst minimising costs in comparison to surveys conducted by Field interviewers face-to-face.

4. What are you doing to ensure good response rates?

Achieving the highest possible response rate is very important in order to maintain data quality, reduce non-response bias, and ensure that the sample is as representative as possible. We have employed a number of strategies to encourage people from the selected addresses to take part in the research, including:

Keeping the survey open for 6 weeks to allow enough time to participate
Offering an incentive for taking part
Ensuring the survey is straightforward to complete and not too long
Creating engaging communication materials
Spacing out communication appropriately:
- After one week of no response, a reminder letter is sent
- After three weeks of no response, a second reminder letter that also contains a paper questionnaire and pre-paid return envelope. This enables participants to complete on paper if they would prefer this to the online method.

5. How have you tried to reduce bias with this research approach?

We want to ensure that the responding population is representative of the population exposed to night-time aviation noise around the selected airports. We want to make sure that we receive responses from a range of people, backgrounds and attitudes. We have tried to reduce bias by doing the following things:

A stratified random[7] sample of addresses around each selected airport were chosen to ensure that a range of night-exposure experiences are included in the sample. This means we have ensured the sample includes residents living in noise bands ranging from 35dB - >60dB.
Inviting households to take part in a study about issues within their local environment and neighbourhood. Aviation noise was not explicitly mentioned in order to reduce non-response bias[8]. This approach was agreed to be the best balance of reducing non-response bias whilst maintaining relevance to the study content and follows a similar approach to previous noise surveys such as SoNA 2014.
Up to two adults per household can take part in the online survey and participants can choose which two participate. This ensures that the last stage of sampling is still random.

Sampling and data collection

1. How have you identified the people that have been invited to participate?

The target population of this study is all residents living near Heathrow, Gatwick, Luton, Stansted, Manchester, East Midlands, Bristol and Glasgow airports that are exposed to night-time aviation noise. Using the postcode address file (PAF)[9], we have identified a list of all the addresses in the target population and linked these addresses to data on night-time aviation noise exposure level, socio-economic status of the area, exposure to night-time road and rail noise, and proportion of the population in an area belonging to Black and Minority Ethnic (BME) groups.

In order to characterise the relationship between night-time aviation noise exposure and outcomes such as annoyance and sleep disturbance, we have divided the target population into smaller strata based on their night-time aviation noise exposure.

Our aim is to survey a roughly equal number of respondents in each night-time aviation noise strata. We have drawn a stratified random sample of addresses within each strata and invited up to two people in each household to participate in the survey.

2. How will the study be representative?

In order to ensure the sample is representative, prior to drawing the sample of addresses we sorted the target population within night-time aviation noise bands according to the stratification variables: airport, socio-economic status, exposure to night-time road and rail noise, and proportion of the population in an area belonging to Black and Minority Ethnic groups. We then selected a systematic sample (with a random start)[10] of addresses within each noise strata. The stratification ensures that we have sampled addresses with a wide range of characteristics. For instance, within each strata we will have selected addresses around all eight airports; from areas with high, medium, and low levels of socio-economic status; from areas with high, medium, low and negligible amounts of night-time road and rail noise exposure, and addresses in areas with varying proportions of BME residents.

3. What sources of data have you used for sampling participants, including data sources relating to aviation noise exposure?

The night-aviation noise data used in sampling is 2022 Estimated L_night Airport Noise Exposure Data. This data has been estimated using 2016 L_night noise grids obtained from the Department of Environment, Food and Rural Affairs (DEFRA) and the Scottish Government as generated under their respective Environmental Noise Regulations. The noise exposure grids have been adjusted by the Civil Aviation Authority to account for changes in the number of night-time aircraft movements between 2016 and forecast for 2022. The lowest continuous noise contour value reported differs by airport. Below the reported lowest noise contour value, we applied an approximation using overflight data to identify addresses around each airport exposed between 35 dB L_night and the lowest reported noise contour.

4. How have you identified the airports you’re surveying around, and which airports are they?

We classified all commercial airports in the UK according to the number and timing of night-time aviation movements, approximate number of residents exposed to night-time aviation noise, geographic location, urban/rural status of communities exposed to night-time aviation noise, and presence and timing of restrictions on night-time flights. Airports without night-time flights were excluded. From this list, we purposively selected eight airports to include those with a wide range of characteristics. These are Heathrow, Gatwick, Luton, Stansted, Manchester, East Midlands, Bristol and Glasgow airports.

5. Why are more airports not included, and why is there not an airport included that is in Northern Ireland or Wales?

There are a few reasons why we did not include more airports in this study, in the context of fixed time and resource constraints. First, a considerable amount of time and resources go into preparing the sample frame and exposure data for analysis around each airport. Second, given a fixed number of overall responses to the survey, we wanted to ensure robust numbers of respondents around each airport.

There was not an airport in Wales that met the criteria of the study due to night-time noise exposure being low around airports in Wales. Belfast City Airport does not have night-time flights, and therefore did not meet the criteria. We did consider Belfast International, but ultimately chose other airports because of the relatively small population exposed to night-time aviation noise around this airport.

6. How will you collect the data?

Data is being collected through an online survey. Those who don’t want to complete online can take part by completing the survey on paper instead. Those who consent to being contacted about the objective sleep study and take part, will be involved in recording their sleep for a one-week period using a Bittium Faros 180 device.

7. How will data I provide be handled and stored?

We take great care to protect the confidentiality of the information people give us. NatCen will handle all data in accordance with the UK General Data Protection Regulation (UK GDPR).

NatCen, St George’s and DfT will store data in line with ISO27001, ISO 20252 and Cyber Essentials Plus certification. Only staff working on the study will have access to your information and their access will be removed when no longer required.

For more information about how we deal with personal information you can read the privacy notice here: www.natcen.ac.uk/annesurvey/privacy.

8. Has this sampling approach been tested?

The sample frame for this study (i.e. the postcode address file (PAF)), is the most common sample frame of addresses used in surveys in the UK. It is used by many large-scale national surveys including the National Travel Survey, British Social Attitudes Survey, and the Annual Population Survey. It is common practice to select a stratified random sample of addresses to participate in PAF surveys to ensure that addresses from many different types of areas are included in the sample. We tested this approach in a pilot study around Manchester, Heathrow, East Midlands and Glasgow airports. The pilot study used a slightly different sample design to the mainstage so that response rates of addresses in different noise strata could be tested and oversampling of addresses in high noise areas could be used to inform the mainstage study sampling strategy.

Links to other research

1. How does this research differ from other studies in this area, such as the Survey of Noise Attitudes (SoNA) 2014 and the work the CAA are currently undertaking on attitudes to aviation noise?

The Survey of Noise Attitudes (SONA) 2014 was undertaking to understand people’s attitudes to noise from various sources, including from fixed-wing aircraft. SONA sampled participants based on their day-time aviation noise exposure, so whilst it asked a few questions relating to night-time aviation noise, there were limits to the conclusions that could be drawn relating to night-time aviation noise; this was a recognised limitation of SONA.

The Aviation Night Noise Effects (ANNE) study, being undertaken by the Department for Transport (DfT), is focussed on understanding the relationship between night-time aviation noise and sleep disturbance and annoyance. To do this, it samples participants based on their night-time aviation noise exposure. This means any findings from the study will be specific to the night-time period.

The Civil Aviation Authority (CAA) has recently been tasked with developing the new Aviation Noise Attitudes Survey (ANAS) as part of their new Noise Advisory Functions. ANAS is expected to build on lessons learnt from SONA and previous preparatory work undertaken by NatCen on behalf of the Independent Commission on Civil Aviation Noise (ICCAN) in 2021⁶. Whilst the full scope of ANAS is to be finalised, its focus will be to gather data about experience of exposure to day-time aviation noise. ANAS is expected to launch in 2023. In contrast, the ANNE study's focus is to gather data about night-time effects on annoyance but also, the impacts exposure to aviation night-time noise has on sleep disturbance. In fact, ANNE will be the first study of aviation noise effects on sleep disturbance in the UK for 30 years.

2. How has this research adopted any findings from NatCen’s recommendations[11] for a new aviation noise attitudes survey to the Independent Commission on Civil Aviation Noise (ICCAN)?

This research study is following the recommendations that were given to the Independent Commission on Civil Aviation Noise by:

Selecting a range of noise exposure experiences as detailed above
Selecting addresses exposed to the lowest levels where possible
Using a purposive sampling method to select the airports included in the study
Including key questionnaire content such as socio-demographic characteristics, standardised wellbeing measures and non-acoustic factors

Timelines

1. When will the research be in field?

The research is broadly split in to two phases. The first phase, involving a cross-sectional study, will be in field in the second half of 2022. The second phase, which involves an observational study of a sub-set of participants from the first phase, is expected to be in field during 2023.

2. Why are you undertaking the research outside of the busy summer period?

Fieldwork for the first phase of the study has been planned intentionally for the second half of 2022 to allow for the busy summer period to have just finished. The reason for this is twofold. Firstly, it means participants will be completing questionnaires very shortly after a busy summer season of aviation activity; this maximises memory of the summer. Secondly, it maximises the available sample as fewer people would be expected, for example, to be away on holiday.

3. When will I be able to see the outcome of the research?

The ANNE study is expected to conclude in 2025. The Department will consider undertaking a review of the research ahead of publication.

Research findings

1. How will the outcome of the research be used?

The research is expected to give evidence needed to derive exposure-response functions between night-time aviation noise metrics and sleep and annoyance outcomes, filling a recognised evidence gap. This could be used by the Department to support the ongoing reviewing of night-time aviation policy, to inform future policies for night-time aviation noise exposure and assist with the management and mitigation of health impacts on local communities, as part of ongoing wider assessments of the costs and benefits of night flying.

The research is also expected to support an update to the Departments Transport Analysis Guidance (TAG), which provides appraisal values that can be used to understand the impact that exposure to aviation noise has on annoyance, risk of acute myocardial infarction (AMI), stroke, dementia and sleep disturbance. The research could update the Departments TAG to provide appraisal values specific to night-time exposure.

2. How accurate will the outcome of the research be?

Power calculations[12] have been used to inform our approach to balancing the study resources across the subjective survey and the objective sleep disturbance study. Both studies have been informed by power calculations, which demonstrate adequate power to detect effects of night-time aviation noise on the key outcomes of sleep disturbance (both studies) and annoyance (subjective survey).

All data collected will be checked and reviewed and quality assurance checks will be undertaken on the analysis.

Engagement

1. How are you engaging with communities you’re surveying?

The Department has engaged on this research with communities through its Airspace and Noise Engagement Group (ANEG), as part of routine policy updates, and more specifically through the ANNE study Steering Group. For more information see question [30].

It is best practice to not share specific details about the timing of the research until fieldwork has been undertaken. For this reason, the Department has not shared specific timings of fieldwork with communities we are surveying.

The Department plans to continue engaging with communities, including those we are surveying, through the ANNE study Steering Group. For more information see question [30].

2. How are you engaging with airports you’re surveying around?

In order to support the sampling of participants for the study, suppliers and the Department engaged with those airports around which fieldwork was undertaken. This was necessary in order to explain to the airports what the study was seeking to do, and how, as well as secure the required data to support the design and development of the sampling strategy.

The Department also engaged on this research with airports through its Airspace and Noise Engagement Group (ANEG), as part of routine policy updates, and more specifically through the ANNE study Steering Group. For more information see question [30].

The Department plans to continue engaging with airports, including those we are surveying around, through the ANNE study Steering Group. For more information see question [30].

3. The CAA are also undertaking a project relating to annoyance relating to aviation noise. How does the ANNE study differ and how are you working with the CAA to manage overlaps/differences?

The Civil Aviation Authority (CAA) has recently been tasked with developing the new Aviation Noise Attitudes Survey (ANAS) as part of their new Noise Advisory Functions. ANAS is expected to build on lessons learnt from SONA and previous preparatory work undertaken by NatCen on behalf of the Independent Commission on Civil Aviation Noise (ICCAN) in 2021⁸. Whilst the full scope of ANAS is to be finalised, its focus will be to gather data about experience of exposure to day-time aviation noise. ANAS is expected to launch in 2023. In contrast, the ANNE study's focus is to gather data about night-time effects on annoyance but also, the impacts exposure to aviation night-time noise has on sleep disturbance. In fact, ANNE will be the first study of aviation noise effects on sleep disturbance in the UK for 30 years.

4. Do you have a Steering Group for the project, and if so, what is its membership?

A Steering Group for ANNE has been established and used to support project scoping, design and methodology development and reviewing material e.g., results from the Pilot study. The Steering Group membership consists of Department for Transport (DfT) representatives, including representatives from the Departments Transport appraisal and strategic modelling (TASM) team, and representatives from community groups (Aviation Environment Federation), industry (Sustainable Aviation), academia, The Civil Aviation Authority (The CAA), UK Health Security Agency (UKHSA) and the Department for Food, Environment and Rural Affairs (Defra).

[1] https://www.gov.uk/government/publications/tag-unit-a3-environmental-impact-appraisal

[2] European Environment Agency. Environmental Noise in Europe 2020. Luxembourg: Publications of the European Union; 2020

[3] Basner M, McGuire S. WHO Environmental Noise Guidelines for the European Region: A Systematic Review on Environmental Noise and Effects on Sleep. Int J Environ Res Public Health 2018;15:519.

[4] Basner M, Witte M, McGuire S. Aircraft Noise Effects on Sleep-Results of a Pilot Study Near Philadelphia International Airport. Int J Environ Res Public Health 2019;16.

[5] Hahad O, Kroller-Schon S, Daiber A, Munzel T. The Cardiovascular Effects of Noise. Dtsch Arztebl Int 2019;116:245-+.

[6] Respondent engagement for push-to-web social surveys – Government Analysis Function (civilservice.gov.uk)

[7] Stratified sampling is a method of random sampling where the sampling frame is sorted by certain characteristics. A systematic sample is drawn so that the sample is representative of the characteristics chosen. See question 13 for more information about which stratification variables were chosen.

[8] Non-response bias occurs when those who do not complete the study are systematically different to those who have completed the study.

[9] The postcode address file (PAF) is the Royal Mail’s up-to-date UK address database.

[10] In systematic sampling with a random start, we first calculate r, a random number between 1 and the sampling interval s. We then select the rth address into the sample and every sth address after that until we have reached the total number of addresses to be sampled in each strata (n).

K= total number of addresses in each strata
n=the number of addresses to be sampled in each strata
s= sampling interval which is calculated as K/n
r = random number in between 1 and s

[11] Designing an aviation noise attitudes survey; ICCAN; June 2021

[12] Power calculations are used to ensure that an adequately sized sample is achieved for the study. If a sample size is too small, we may not get an accurate picture of the whole population and the study may not provide a precise estimate. If a sample size is too large, whilst the results will be more accurate, there is a risk of unnecessary complexity and costs being introduced to the study.