The impact of transport induced environmental noise on the wellbeing of residents adjacent to major traffic infrastructure routes in Northern Ireland

Abstract

Background: Noise pollution has been identified as a potential major environmental health problem in Europe, with an estimated 20 million people suffering from annoyance associated with exposure to road traffic noise. In Northern Ireland it is recognised that there is a high level of dependence on private vehicles for transportation. This means that there is the potential for many people across this geographic area to experience high levels of road traffic noise, particularly in residential dwellings close to transportation corridors. A literature review has demonstrated that there are numerous health impacts associated with exposure to high noise levels. Although the strength of the findings of previous research is variable, the prevalence of certain conditions has been found to increase with exposure. However, several factors e.g. age, gender and sensitivity to noise, have been found to influence this impact. Therefore, in order for this study to be reflective of the previous research studies, the method adopted needed to be able to assess these factors.

Thesis Aim: To investigate the exposure level of noise experienced by residents who live along major roads at selected locations across Northern Ireland. Then to compare the data from these primary measurements to the results of the Department of Agriculture, Environment and Rural Affairs (DAERA) strategic noise mapping. This strategic mapping was undertaken to meet the provisions of the Environmental Noise Directive. This doctoral study chose to test the reliability of the mapping approach adopted to identify the population exposed to the highest levels of noise. Using some of the same locations, this research also sought to assess how exposure to high levels of road traffic noise impacts on the mental and physical health and wellbeing of residents.

Methods: Two different measurement methods were utilised in this research. The first approach adopted was for the collection of road traffic noise data. Measurements were taken according to current industry best practice at selected sites across Northern Ireland. Twelve sites were selected based on the inclusion criteria. The data collected from each site was compared to various standards and guidelines and the results from the strategic noise mapping. The second approach utilised a mail drop questionnaire survey to gather health and wellbeing data from the residents who were identified as living in areas with high levels of noise. The questionnaire was based around the SF-12 survey which has been utilised in previous health and wellbeing studies. This survey proforma has been extensively studied and is an internationally recognised measure of health. Other sections were added to the questionnaire to allow confounding factors to be examined. These were drawn from other surveys and included demographic and lifestyle factors which can impact on health, personal perception of noise and health conditions. The inclusion of these factors was based on a review of the literature which identified their association with noise exposure and contribution to the impact of noise. The statistical analysis was carried out using the SPSS software, with linear regression modelling being adopted in this phase of the research. The data obtained from the SF-12 survey was used to generate a Physical and Mental Health score which could be compared to the normative health of the general population.

Results: The results from the noise monitoring showed that the noise levels at each of the sites exceeded the WHO Guidelines for Community Noise at both the moderate and serious annoyance levels. Furthermore, the field measurements confirmed that the noise levels exceeded the WHO Night-Time Noise Guidelines for Europe and the Environmental Noise Guidelines for the European Region regarding road traffic noise. In terms of meeting the criteria for declaration as a Candidate Noise Management Area (CNMA), six of the chosen twelve sites reached the required level of 75 dB LA10,18Hr for at least one of the days during the measurement period. Overall, the majority of the sites were comparable to the results from either the second or third round of mapping and only four did not match the results from either. For the health and wellbeing survey, the initial response rate was lower than the anticipated number of responses (n=185), with additional rounds of surveying carried out to support, supplement and strengthen the findings (n=222). As the number of responses was lower than envisaged, the twelve sites were collapsed into four noise bands, to ensure rigour within the research. The results showed that 60% of the participants reported experiencing annoyance caused by road traffic noise at least ‘Sometimes’ and 56.6% reported perceiving the annoyance they experienced at a high level. When the results from the SF-12 survey were compiled, the physical health scores were comparable to the normative value of the general population, whereas the mental health scores were lower than the general population. When the linear regression was carried out the following variables were identified as being statistically significant (p=>0.05) for the Physical Health scores data: age, household income, education, smoking, physical activity, alcohol consumption, psychological impact of noise and the noise banding range. For the Mental Health scores data, the alcohol consumption and psychological impact of noise variables were statistically significant. In terms of the prevalence of certain health conditions among residents who live in areas with high road traffic noise levels, the majority of the conditions assessed were similar to the prevalence experienced among the general population of Northern Ireland. However, the results demonstrated that the occurrence of cardiovascular disease, mental health conditions and asthma and other respiratory conditions were higher that the national average and could possibly be linked to the noise exposure at the test locations.

Conclusion: The results of the noise monitoring carried out all exceeded the guideline levels published by the WHO (1999; 2009; 2018). Based on the field observations it could be assumed that there is a high likelihood of annoyance occurring and this could potentially be associated with health impacts occurring among the population. This correlated with the results regarding the perception of noise from the questionnaire. When the results of the monitoring were compared to the findings of the strategic mapping, several of the sites did not correspond to the published findings, although most did to either the second or third round of mapping. However, all were in excess of the guideline levels, which means that consideration should be given to adapting the criteria so that more areas where potential negative effects are likely to be experienced are identified. The results from the health and wellbeing survey showed that road traffic noise is more likely to have a larger impact on mental health than physical health. Although, the linear regression modelling showed that exposure to the highest levels of noise reduced physical health among the sample population. However, a greater number of responses would help to strengthen the findings of the study, which could involve including a larger number of sites.

Date of Award	May 2021
Original language	English
Sponsors	Department for the Economy
Supervisor	Brian Solan (Supervisor), Lindsay Shaw (Supervisor) & Paul Slater (Supervisor)