Sound is the least recognised form of pollution, and therefore it is also the least regulated, although laws to control noise levels are now being put into place. Many of us are exposed to high levels of noise at work, when travelling, when shopping, and, more seriously (from a psychological point of view) in the home, where there can be intrusive noise from traffic, domestic appliances, garden appliances, and especially if you're living in badly constructed apartments or terraced homes, from your neighbours.

Noise generated indoors includes refrigerators, washing machines and dishwashers, central heating pumps and boilers, flushing toilets, flourescent lighting, vacuum cleaners, televisions and stereos. The table below gives a list of typical sources of noise pollution, and the level of noise (in Decibels, or dB), they produce. The Decibel is a measure of sound pressure level, that is, the magnitude of the pressure variations in the air. A 10dB increase is a doubling of loudness.

Decibels (dB)	Related Sounds
130 - 140	Jet engine at 100ft
120	Threshold of Pain - Loud thunder, car horn at 3ft
110	Nightclub speakers at 4ft, rock concert, pneumatic drill
100	Chainsaw, lawnmower, motorcycle
90	Heavy lorry, hair-dryer
80	Danger level - Inside small car, noisy office, alarm clock at 2ft
70	Busy shopping street, vacuum cleaner, washing machine
60	Normal conversation at 3ft
50	Quiet street, inside average home
40	Quiet office, quiet conversation, refrigerator
30	Ticking watch, whispered conversation, library
20	Quiet country lane
10	Leaves rustling in wind
0	Threshold of hearing

There are several reasonably simple things you can do to at reduce noise levels in your home:

• If your home is sited near a busy road, build a high wall or grow a dense barrier of trees to block some of the noise
• Move living and bedrooms to the quiet side of the house
• Don't place fridges, freezers, washing machines and other noisy household appliances near partition walls
• Don't wear shoes indoors - wear slippers or go barefoot
• Seal gaps around doors and windows; install secondary glazing
• Add window shutters or heavy curtains
• Carpet the floor and put up fabric wall hangings
• Replace old, noisy boilers and other appliances
• Add pleasant noise, such as a waterfall or wind chimes (but don't annoy the neighbours with these!)

There are also more extreme measures you could take, especially you're living in an apartment or flat, such as adding soundproofing to walls, floors and ceilings!