Relation of long- and short-term atmospheric sulfur concentrations to sulfate deposition in New York State

Records from 1965-80 indicate an annual decrease of 1.9% in sulfur dioxide emissions upwind of New York, an annual decrease of 1.5% in atmospheric particulate sulfate concentration in New York, and an annual decrease of 2.0% in sulfate-deposition rate in New York. Sulfate-deposition rates in bulk sampling in New York during 1965-80 were approximately 40% of the average sulfur-emission rate for the Northeast. Sulfate-deposition rates in bulk and wetfall collectors were nearly equal and were five times greater than in the dryfall collector. Scavenging ratios for sulfate averaged 8.9 ?? 105; those for sulfate plus sulfur dioxide averaged 4.6 ?? 105. Sulfate concentrations in wet deposition averaged more than twice those estimated from published regional-scale washout equations, whereas those in dry deposition averaged only 22% of those computed from deposition velocities of 0.1 cm/s for sulfate and 1.0 cm/s for sulfur dioxide. Discrepancies in the dryfalls are attributed to inefficiency of dryfall-collection equipment. -from Author