MEASUREMENTS OF FORMIC AND ACETIC-ACID LEVELS IN THE VAPOR-PHASE AT DAYALBAGH, AGRA, INDIA

Acetic and formic acid concentrations were determined in the vapour ph ase at ground level at Dayalbagh, Agra, during the winter and summer o f 1992-1993. Ion chromatography was used to measure the species. Yearl y means were 1.7 +/- 1.6 ppbv for acetic acid and 1.3 +/- 1.4 ppbv for formic acid (N = 137). Average winter mixing ratios (N = 60) for acet ic acid and formic acid were 1.8 +/- 1.6 and 1.4 +/- 1.4 ppbv, respect ively, and the corresponding summer levels (N = 77) were 1.3 +/- 1.2 a nd 1.1 +/- 1.2 ppbv but seasonal variation was not statistically signi ficant. These concentrations are within the range reported at other si tes worldwide. The FIA (formate-to-acetate) ratio showed a diurnal var iation with higher averages in the day (1.2) than at night (0.45). Wit h respect to wind direction, the W sector appears to be the cleanest a nd is associated with the lowest mean concentrations of acetic and for mic acids; local sources as well as the ones on a larger scale appear to contribute to the levels recorded in this study. Copyright (C) 1996 Elsevier Science Ltd