Factors
When thinking of living relatively close to an airport, most people will show concern about the noise that will endure in their daily routine, even if the aerodrome has little activity.
Noise impact in the population can be defined as the sum of the received dose of noise and the reaction or discomfort of the affected people.
Noise impact = dose of noise + discomfort
There are some examples of non-acoustic factors that may influence the attitudes of the population to cope with the nuisances:
Perception of costs and benefits
According to a survey by Ruud Vader, airports are the source of many benefits for their social milieu: the airports provide jobs, infrastructure, economic performance and general wellbeing. But these benefits involve harm to the environment so, in order to balance costs and benefits, some airports have implemented "green" measures that improve the relationship between the airport and their environment.
Confidence
Total confidence between an airport and the community can only be established if people believe that the information received is accurate. One of the best ways to achieve this is to provide data that can be easily confirmed by a person without the need for technical expertise. Nowadays it is relatively easy to verify the information about the noise from an aircraft or a flight path, so data must be clear and concise.
Preventability
Aircrafts use corridors identified as Preferred Noise Routes (PNR) designed to prevent urban areas whenever possible. Aircrafts may deviate from these routes to others called Non Standard Departures (NSD) when instructions from air traffic control indicates so, for weather reasons or for operational and safety reasons.
Future expectations
The level of discomfort can be perceived not only due to the frequency and the noise of aircraft movements. The tolerance to aircraft noise is also affected by factors such as people's expectations in terms of quality of life or by their understanding of social and economic consequences of limiting the growth of the airport.
Discussion groups
The investigation of how the noise is perceived by population, the reasons of nuisances and the ways to confront them by means of discussion groups achieves a social opening and an improvement of the quality of life.
Knowledge of the impact
Not all the individuals have the same contextual situation (economic, social, cultural, etc.). The measures are effective only when the individual impact that causes specific nuisances is known for each injured person and for each context.
Equity of the process
Several studies have found that noise discomfort increases significantly when the affected people are exposed to a lack of transparency in communications or to a lack of information. Experiments show that knowledge of "procedural equity" and "non-procedural equity" has opposite effects on the reactions of the society against noise nuisances.
Perception of influence and noise control
The importance of control of active noise – measured by noise audiometer- must be considered without forgetting the passive noise – psychological distress- . Constant monitoring of the evolution of noise at different times of the day is essential, as well as analyzing the consequences caused by noise together with affected population in a personalized manner.
Source transparency
According to the studies made, this is the most important factor. The social feedback must be constant or non-acoustic measures may end up in citizen despair. If sources are not transparent and the information received is weak or manipulated, there will be no such feedback.
Analysis of nuisances
Surveys and questionnaires can be carried out in order to analyze the social concern for the acoustic discomfort. Citizen cooperation can be crucial to the relationship between airport and residents.