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Sulphur dioxide in Greater London, 1931–1985

1987; Elsevier BV; Volume: 43; Issue: 2 Linguagem: Inglês

10.1016/0269-7491(87)90069-8

1873-6424

D. P. H. Laxen, Mark Thompson,

Atmospheric and Environmental Gas Dynamics

Annual mean sulphur dioxide concentrations measured at County Hall in central London between 1931 and 1985 showed no clear trend until 1963/64, when a steady decline set in. Results for a number of sites across London for the period 1964/65 to 1984/85 have been divided into three geographic zones: the City of London, a central zone and an outer zone. A steady downward trend is evident in each zone, but is most pronounced in the City of London, especially after 1970. This could reflect the successful introduction of a 1% limit on the sulphur content of oil used within the City, but not elsewhere in London. Annual mean sulphur dioxide concentrations are now around 40 microg m(-3) in all three zones. Highest daily sulphur dioxide levels in both summer and winter have also declined steadily during the period 1964/65 to 1984/85, while at the same time the seasonal pattern of higher winter peaks in daily maxima, which was strong at the beginning of the period, has been virtually eliminated.