IMPORTANT NOTE: This is not a medical site. You should always discuss medical matters with your doctor.
One of the worst things for preventing a good night's sleep is noise. For our ancestors, strange noises during the night possibly meant a predator approaching. For this reason we probably evolved to be sensitive to unusual noises during the night. In today's society what was once an advantage can now be a problem.
The key word is "unusual". So long as the noise levels are not too extreme, then over time we can adjust to most sounds. However it only takes a slight change from what we're used to for external noise to seriously disturb our sleep - although we all know some lucky people who can apparently sleep through anything in comfort. I sometimes wonder how their ancestors survived to pass on the "deep sleep" gene!
Silence can be as bad as noise. Some city folk find it difficult sleeping in the country because it is too quiet.
The best solution to noise pollution is, of course, to block it out. Something as simple as double glazing the room can make a huge diference. Unfortunately for some this isn't a practical option - or is insufficient. This is also ineffective if the cause of the noise is internal - for example tinnitus.
A simple alternative to blocking out the sound is to mask it with white noise or other ambient sounds. Even if unwanted noise isn't ruining your sleep some manufacturers claim that investing in a sound conditioning solution could help to make your sleep better and more deep. It might also help you to relax or concentrate if used during the day.
Sleep Sound Machines
A more sophisticated option is to buy a dedicated sleep sound generator. These sound conditioning machines are available in a variety of options, everything from simple white noise generators to complex devices with the ability to mix dozens of different ambient sound combinations.
It's tempting to just buy the sound machine with the most features. However you should ask yourself whether you are really likely to use them all. Some users will love to experiment with all the options, others will just find two or three sound combinations and stick with them. It probably depends on how much you like gadgets! As always, buy quality.