Having lived in various places all over the world for the past 9 years of my life, one thing stood out to me throughout this time, and now in particular. From a quiet place on the countryside in Sweden, I moved to Manchester for my studies. When I first arrived there, I felt the city was very noisy, a feeling which gradually reduced as I presumably got used to the noise levels there. From Manchester I moved over to Saitama in Japan, an enormous city right next to Tokyo with a considerable amount of noise during the day, and buildings that have little to no sound insulation. With the exception of particularly loud noises, I again adapted to the sound levels in the country, which at the time, I felt was no more than a natural response in terms of how much attention we pay to the noise. If I'm distracted by work or other activities, I have little reason to dwell on the sounds of driving cars and talking people.
The thing I couldn't explain purely by the 'paying attention' argument however was when I moved back to the Netherlands, to an apartment with excellent sound insulation. My apartment is located in front of a somewhat larger road, and cars pass by almost consistently. However, when I moved in I could barely hear these cars driving past, something that stood out to me as fairly pleasant. I thought a little bit of ambient music would kill the sound of these vehicles driving past altogether.
Now skip ahead one month, and I can hear the cars almost as if I'm standing next to them, an exaggeration of course, but the sound is much clearer than it was when I moved in. I know that nothing has changed in terms of insulation and I know that no windows are open. Strangely the only thing that appears to have changed is the clarity in which I perceive this noise, as none of the other people whom I've asked seem to share the same opinion (that is, that the noise has grown louder). This made me wonder - does our hearing adapt to noise pollution, and if so, how does it work?