THE INFLUENCE OF WIND DIRECTION, CIRCULATION TYPE AND AIR-POLLUTION EMISSIONS ON SUMMER VISIBILITY TRENDS IN SOUTHERN ENGLAND

Summer visibility data from a rural site in southern England are analyzed in different wind directions and Lamb circulation types over a 14-year period and related to possible air pollution source areas. Increases in visibility are evident in most wind directions and circulation types after the 1973 oil crisis, indicating that climatic change is not the major cause of visibility improvement. It is suggested that aerosol SO42- formation from precursor emissions within the U.K. may be important and that decreased U.K. SO2 emissions are more important for visibility improvement than changes in long distance transport of air pollution from continental Europe. © 1990.