Variation in rainwater chemistry, and its relation to synoptic conditions, at a site in North‐West England

Detailed studies of the chemistry of rainwater from 28 storms have been made at a site near Lancaster, England, using a specially‐designed sampler. Major cations and anions show high concentrations in the first rainfall collected for each event, and rapidly decrease to low but finite values in later samples. High initial concentrations are attributed to dissolution of aerosols and dry deposits previously collected on the funnel. The total ionic contribution to the rainwater samples by this process can be related linearly to the length of the dry period preceding the storm. Comparison of rainwater chemistry and storm trajectories suggests that airmasses which have passed over industrial areas have rainwater chemistry (high SO₄, Ca; low Na, Cl) which is distinct from that associated with storms of marine origin (high Na, Cl; low SO₄).