Chemical Analysis of Aerosol Particles and of Gas Traces on the Island of Hawaii

Aerosols of two different size ranges with radii between 0.08 < r < 0.8 μ (large particles) and 0.8 < r < 8 μ (giant particles) were analyzed for NH₄⁺, Cl⁻, SO₄⁻ and NO₃⁻ Parallel with this, the concentration of corresponding gas traces, that is of NH₃, chlorine components, SO₂ and nitrogen dioxide was measured.

The results show that the giant particles consisted almost entirely of sea spray. Their content of NO₃⁻ was small compared to the data from the East Coast of the United States (Round Hill, Massachusetts and Homestead, Florida).

The Cl− content of the large particles was less than 1.5 % of that of the giant particles, confirming previous data which showed that the sea spray is almost completely restricted to particles larger than 0.8 μ radius. The large particles contained NH4 in amounts comparable with the other components, indicating the presence of other than sea spray nuclei in this size range. The NH₄ is probably present in the form of (NH₄)₂SO₄.

Both particle sizes were completely missing in the raining orographic clouds.

All gas components were found to be present and the concentrations did not fluctuate very much. They were washed out, to a small degree, if at all, by rain.