Uptake of gas-phase aldehydes by water surfaces

The uptake of gas-phase formaldehyde and acetaldehyde by water droplets was measured along with mass accomodation coefficients. Formaldehyde uptake is predictable, but that of acetaldehyde as short gas-droplet contact times is greater than predicted due to a chemisorbed surface complex at the gas-water interface that may explain the high measured concentration of acetaldehyde in clouds relative to formaldehyde. The small uptake coefficients suggest that this may be the limiting factor in aldehyde uptake into clouds. 36 refs., 10 figs., 3 tabs.