The condensation method has been used at a variety of locations in the southwestern United States to determine the concentrations of formaldehyde, formic acid, and the group of organic acids coeluting with acetic acid (hereafter called ''acetic acid''). Urban concentrations were typically as follows: formaldehyde, 1.4 ppb; formic acid, 3 ppb; and acetic acid, 4 ppb. In remote areas, formic and acetic acid concentrations were typically 0.9 ppb and 0.6 ppb, respectively. The data suggested that (1) in forested and probably desert regions, there is a substantial natural production of organics, particularly the acids, during summer, presumably by vegetation; (2) at least in the southwestern United States, in summer, there is a relatively weak coupling between the cycles of formaldehyde and formic acid; (3) near San Diego, organic acid lifetimes may be much shorter than previously expected, i.e., only several days; (4) at the lowest concentrations observed, partitioning of the organic acids into cloud water would give aqueous concentrations similar to those found in rain. ¿ American Geophysical Union 1988