Long-term deposit at Rothamsted, southern England

Monthly rainfall analyses are available for Rothamsted and the surrounding area since 1853. Long records exist for NH₃, NO₃ and Cl, while SO₄ and pH measurements are less complete. The most striking change over the period is a shift in the seasonal distribution of the nitrate in the rain which has changed the deposit from <0.1 g m^-2 yr^-1 in the mid-19th century to ~0.2 g m^-2 yr^-1 at present. The pH, initially 4.7 in 1930, starts to decline only recently by about 0.5 in the last 10–15 years. Chloride and ammonia show little change. Sulphate levels may have doubled since 1880 but there is no way to check their reliability.