The first two tables give the average number ofdays per site when air pollution levels were moderate or higher, in each yearfor which data are available, using sites which form part of the UK monitoringnetwork.The third table presentsdata from the Edinburgh black smoke/sulphur dioxide monitoring site whichwas operational from 1966 to 1996.Local authorities alsoundertake air quality monitoring, but the relevant data from the City of Edinburgh Council area are not held centrally.Scotland1 1987 1988 1989 1990 1991 1992 1993 1994 1995 Rural network (3 sites) 17.3 25.7 27 35 28.7 32.3 15.3 32.7 23.7 Urban network (Edinburgh site only) - - - - - - 20 18 29 Edinburgh 19922 1993 1994 1995 Carbon monoxide 0 0 0 0 Nitrogen dioxide 0 0 0 0 Ozone 0 0 4 6 Particles 6 4 3 18 Sulphur dioxide 2 16 12 10 Total 8 20 193 344 Notes:1.