Very low temperatures in the winter are common only in areas such as the mountainous districts of the interior of Scotland. Fog, mist, and overcast skies are frequent. The United Kingdom emits significant quantities of sulphur dioxides, which contribute to air pollution both at home and in Scandinavia. Urban air quality is also threatened by a burgeoning transport sector. The water quality in the UK's rivers and beaches has improved little over the last 20 years, but an investment programme is under way to improve water treatment.
Urban waste poses an increasingly difficult problem, as landfill sites become scarce.
North Sea oil fields have provided the country with important trade wealth and energy, although they have contributed to serious oil pollution. The country's early nuclear industry disposed of radioactive waste by ocean dumping, leaving a legacy of contamination, particularly in the Irish Sea. The country's long tradition of environmental conservation dates from 1014, when King Canute proclaimed the Forest Laws. Private reserves and estates account for a large proportion of the country's protected land, and there are numerous local conservation and preservation trusts throughout the country. Man and the Biosphere Program.