Average weekly monitored black smoke concentrations (parts per million) in the city of Newcastle upon Tyne, 1970 to 1979 inclusive. We thank Tanja Pless-Mulloli (University of Newcastle upon Tyne) for providing these data. Columns are: week: week counter (1=first week in January 1970) BS: average black smoke concentration temp: average temperature (degrees centigrade) fit: fitted stochastic trend