[en] Nuclepore filters coated with an alkaline solution were used for collection of sulfur dioxide in the air. The best alkaline solution for the coating was 20% potassium hydroxide with 10% glycerol or triethanolamine. 25 mm diameter Nuclepore filters could be coated by simple procedures with potassium hydroxide, with about 10% error, and the average coated amount of potassium hydroxide was 125 μg for a filter. The collection efficiencies of the coated filter for sulfur dioxide concentration, flow rate, and loading were examined using known concentrations of sulfur dioxide. A collection efficiency of more than 98% was observed below 4.0 1/min flow rate (19 cm/s air velocity) at 0.054 ppm sulfur dioxide, 25⁰C and 30% r.h. The capacity for the coated filter was 50% loading, equivalent to 25 μg sulfur dioxide, and higher loadings caused lower collection efficiencies. Sulfur dioxide collected on the coated filters was directly analyzed by particle induced X-ray emission (PIXE) using 5 MeV protons, which has high sensitivity at nanogram levels, and the results of PIXE analysis of sulfur dioxide agreed well with the West Gaek method. The coated filter and PIXE analysis were used for measurements for sulfur dioxide at the coast and ocean in north Florida, a relatively unpolluted area, during February 1979. Their average concentration was 1.3 ppb (n = 13). (orig.)