Abstract
Air quality data obtained at a rural site in northwest England are presented. Concentrations of SO sub(2) , NO sub(2) , NO, and O sub(3) were measured continuously, while 24-hr average concentrations of NO sub(3) super(-) , SO sub(4) super(2) super(-) , NH sub(4) super(+) , Na super(+) , K super(+) , Ca super(2) super(+) , Mg super(2) super(+) and Cl super(-) were determined. Excluding pollutants from a nitric acid/ammonium nitrate fertilizer works within 2 km of the main measuring sites, the upper decile of hourly concentrations was 19 p.p.b. for SO sub(2) , 22 p.p.b. for NO sub(2) , and 52 p.p.b. for O sub(3) during the period May-Sept. 1977. The upper decile of 24-hr concentrations was 12 mu g m super(-) super(3) for SO sub(4) super(2) super(-) , 4 mu g m super(-) super(3) for NO sub(3) super(-) , and 4 mu g m super(-) super(3) for NH sub(4) super(+) . The concentrations measured are typical of those reported for rural and semirural sites in Europe and North America. The results are interpreted in terms of local and synoptic-scale meteorological influences. It is concluded that the highest concentrations of the pollutants SO sub(2) , NO sub(2) , NO sub(3) super(-) , SO sub(4) super(2) super(-) , and NH sub(4) super(+) are generally associated with regional transport of polluted air masses, rather than with more local sources. Predictably, Na super(+) , Mg super(2) super(+) , and Cl super(-) have their sources in marine aerosol, whereas K super(+) and Ca super(2) super(+) are predominantly soil derived. A study of total pollutant deposition showed values typical of rural sites in Britain.