Assessing the relationship between objective and subjective indicators of residential exposure to road traffic noise in the context of environmental justice

Abstract

Noise action planning according to the EU Environmental Noise Directive aims to improve people's health. Although health inequalities exist, the Directive does not address social inequalities in residential exposure to road traffic noise. In multivariate regression analyses based on two urban study populations, we assess the relationship between objective and subjective indicators of residential exposure to road traffic noise as an issue of environmental justice. Residential neighbourhood satisfaction, socio-demographic and -economic, health-related and noise-related attitudinal factors were included as covariates additionally explaining the subjective response to road traffic noise (noise annoyance). Our results underline the need to select, operationalise and examine noise-related indicators very carefully, as objective noise exposure predicts noise annoyance insufficiently. Otherwise, urban environmental planning might miss environmentally unjust situations and fail to initiate distributive and procedural environmental justice.

Keywords:

• residential exposure to road traffic noise
• noise annoyance
• validity of indicators
• environmental justice

Acknowledgements

First and foremost, the authors are grateful to the three anonymous referees whose critical reading and comments helped to improve the manuscript significantly.

Moreover, they wish to thank Martina Kohlhuber, Department of Environmental Health, Bavarian Health and Food Safety Authority, for her expertise in environmental epidemiology and valuable comments on previous versions of the manuscript, Michael Nonnemacher, Institute of Medical Informatics, Biometry and Epidemiology, University of Duisburg-Essen, University Hospital Essen, for his good advice on noise data acquisition and GIS commands, as well as Roland Harhoff, Institute of Epidemiology and Social Medicine, University of Münster, for the validation of noise exposure assignment in GIS. Finally, we thank the staff members of the Environmental Department of the City of Dortmund for their collaboration.

The Institute of Spatial Planning (IRPUD) at the Faculty of Spatial Planning, TU Dortmund University, granted the corresponding author a research fellowship for her doctoral thesis which was additionally supported by the Institute of Epidemiology and Social Medicine, University of Münster and the Institute of Medical Sociology, University of Düsseldorf.

Data collection in the Dortmund Health Study was supported by the German Migraine and Headache Society and by unrestricted grants of equal share from Almirall, AstraZeneca, Berlin Chemie, Boehringer, Boots Health Care, Glaxo-Smith-Kline, Janssen Cilag, McNeil Pharma, MSD Sharp & Dohme and Pfizer to the University of Münster. The SAVE project was financed by the University of Kassel, CESR.

Notes

1. We did not find any association of equivalent income and noise annoyance in our study samples. Due to high loss of observation numbers (missing values) in the income item we did not pursue income in our analyses. Yet, economic conditions might still play a role in the study population; in linear regressions (see paragraph on statistical analysis), financial strain was associated with noise annoyance in one of the studies (Dortmund Health Study (Berger 2012)) after controlling for all other variables used in the final models.

2. Webpage of the project: www.cesr.de

3. Wording of the ‘noise annoyance’ questions was as follows:

• In DHS: How satisfied are you with traffic-related noise in your residential neighbourhood (rail/tram, heavy trucks, and cars)? 1 (very satisfied), 2 (satisfied), 3 (more or less satisfied), 4 (dissatisfied), 5 (very dissatisfied).

• In SAVE: Do you ever feel disturbed by noise in your dwelling (with closed windows) (if yes, read options 2–5)? 1 (never), 2 (seldom), 3 (sometimes), 4 (often), 5 (always).

4. In consideration of the non-linear association between age and (sleep-related) noise annoyance in previous studies (Miedema 2007; Michaud, Keith, and McMurchy 2008), we conducted a sensitivity analysis using age categories in the DHS. However, our results did not give evidence of age-related noise sensitivity.

5. Items of the ‘attitude towards silence’-scale:

1. I expect my flat to protect me from outdoor noise.

2. It is important for me to live in a quiet neighbourhood.

3. Interventions reducing noise levels inside my flat are beneficial to my health.

4. It is important for me to be able to sleep under quiet conditions.

6. Study-specific differences in estimated socio-demographic and -economic effects might result from recruitment strategies leading to different risk constellations underlying these indicators. Concerning background of migration, for example, differences might stem from the nationalities condensed in this indicator. SAVE had mainly engaged residents with a Turkish background of migration representing the majority of immigrants in the Ruhr Area. As a representative sample, the DHS included participants with a variety of nationalities including Eastern and Southern Europe beside Turkey. As a result, DHS participants might vary somewhat in terms of social integration, acculturation, and citizenship.