Noise-related annoyance and quality of life over time
The analysis of the noise-related annoyance over a period of three years was one of the central tasks of the Quality of Life Study. The first surveys took place before the opening of the new North-West runway at Frankfurt airport in October 2011. The curfew on scheduled take-offs and landings between 23:00 and 05:00 hrs also only came into effect as of this month. In 2011, 2012 and 2013 the NORAH team asked people in the Rhine-Main region to what extent they felt annoyed by the noise of aircraft in the previous twelve months. The respondents selected their answers on a scale of 1 to 5: 1 stood for "absolutely no annoyance", 5 for "extremely high annoyance". The scientists used the answers to calculate how severely on average the respondents felt at which continuous sound level. It was found that there were very different degrees of annoyance in the three years. The respondents felt most annoyed in 2012, the year after the opening of the new runway.
Changed noise background
The NORAH team also wanted to know whether the changed noise exposure in the Rhine-Main region had led to a change effect.For this purpose they divided the study participants into three groups. In one group the continuous sound level had decreased between the surveys, in the second group it had stayed the same, and in the third group it had increased. The scientists then looked at the average annoyance for each group.
- In persons, at whose address the noise decreased from one year to the next, the NORAH team was able to establish a positive change effect. In these persons the annoyance was reduced to a somewhat greater degree than the actual reduction in air traffic noise would have suggested.
- In the study participants whose noise exposure had remained the same, a slight negative change effect was observed: although nothing had changed compared with 2011, in 2012 the persons concerned felt somewhat more annoyed. In 2013 the annoyance fell again to some extent.
- A more pronounced change effect occurred in persons at whose addresses the noise had actually increased. They felt more annoyed by the new sound level than people who had already been exposed to similar noise levels for years.
The change effect
When people believe that it is going to get louder in their environment, or when the noise levels actually do increase, then they feel disproportionately more annoyed by noise – experts call this a (negative) change effect. The change effect, however, also works in reverse: when people believe that the noise will be reduced due to measures taken, or when the noise is actually reduced, then they feel less annoyed than would have been expected on the basis of the reduction in noise ("positive change effect").
Quality of life and traffic noise
Noise can influence quality of life – both mentally and physically. In order to identify a possible connection between traffic noise and quality of life, the NORAH team used several scientifically established questions. From the answers of the study participants they then calculated a point score for the mental and for the physical quality of life. They looked at the results over the course of time from 2011 to 2013, but also in comparison with the average value for the whole of Germany.
Particularly with regard to the mental quality of life, but also for physical quality of life, the scientists were able to establish a clear correlation between noise and quality of life: people who felt highly or extremely annoyed by noise had a lower assessment of their mental and, in some cases, physical quality of life than persons who suffer less from traffic noise. They also assessed their quality of life lower compared with the national average.
Noise-related annoyance increased since 2005
NORAH is not the first study to investigate to what extent people in the Rhine-Main region are disturbed by traffic noise. As far back as 2005, the so-called RDF Study commissioned by the Regional Dialogue Forum Frankfurt Airport asked the residents living in the environs of the airport to assess their noise-related annoyance on a scale of 1 to 5. Anyone who selected 4 or 5 was automatically included in the group of the "highly annoyed". The NORAH team adopted a similar approach to calculate how high the proportion of "highly annoyed" persons is for the different noise levels. The result of the comparison: in 2005 there were substantially fewer people in all sound level classes who felt highly or extremely annoyed by air traffic noise. At the three other airports investigated by NORAH the proportion of "highly annoyed" persons was also above the values measured in 2005 in the Frankfurt region.