Abstract
Formic and acetic acids were measured in a scrub-grass savanna and in a nearby semideciduous forest. Gaseous HCOOH and CH3COOH were collected using the mist-scrubber technique, and were determined using ion chromatography. A strong diurnal cycle was observed at both sites, with higher mixing ratios during daytime. Concentrations in the savanna were always higher than in the forest. Most of the time HCOOH/CH3COOH ratios greater than one were recorded at the savanna site, and ratios less than one at the forest site. Boundary-layer mixing ratios in the savanna region, derived from measurements during midday, are 1.3±0.4 ppbv and 0.7±0.3 ppbv for HCOOH and CH3COOH. Dry depositions velocities between 0.5 and 1 cm s-1 were estimated for the savanna region. Atmospheric residence times of <3 days and >5 days were estimated for the rainy and dry season, respectively.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Andreae, M. O., Talbot, R. W., Andreae, T. W., and Harris, R. C., 1988, Formic and acetic acids over the central Amazon region, Brazil, 1. Dry season, J. Geophys. Res. 93, 1616–1624.
Andreae, M. O., Talbot, R. W., Berresheim, H., and Beecher, K. M., 1990, Precipitation chemistry in central Amazonia, J. Geophys. Res. 95, 16987–16999.
Ayers, G. P. and Gillett, R. W., 1988, Acidification in Australia, in H. Rodhe and R. Herrera (eds.), Acidification in Tropical Countries, SCOPE series No. 36, Wiley, Chichester, pp. 347–402.
Chameides, W. L. and Davis, D. D., 1983, Aqueous-phase source of formic acid in clouds, Nature 304, 427–429.
Cofer, W. R., Collins, V. G., and Talbot, R. W., 1985, Improved aqueous scrubber for collection of soluble atmospheric trace gases, Environ. Sci. Technol. 19, 557–560.
Colbeck, I. and Harrison, R. M., 1985, Dry deposition of ozone: Some measurements of deposition velocity and of vertical profiles to 100 metres, Atmos. Environ. 19, 1807–1818.
Galloway, J. N., Likens, G. E., Keene, W. C., and Miller, J. N., 1982, The composition of precipitation in remote areas of the world, J. Geophys. Res. 87, 8771–8786.
Garland, J. A. and Derwent, R. G., 1979, Destruction at the ground and the diurnal cycle of concentration of ozone and other gases, Quart. J. R. Met. Soc. 105, 169–183.
Graedel, T. E. and Eisner, T., 1988, Atmospheric formic acid from formicine ants: a preliminary assessment, Tellus 40B, 335–339.
Hartmann, W. R., 1990, Carboxylic acids in the atmosphere, PhD Thesis, Johannes Gutenberg Universität, Mainz (in German).
Helas, G., Bingemer, H., and Andreae, M. O., 1990, Organic acids over equatorial Africa: results from DECAFE 88, EOS 69, 1066.
Gillett, R. W., Ayers, G. P., and Noller, B. N., 1990, Rainwater acidity at Jaribu, Australia, in the wet season of 1983/84, Sci. Total Environ. 92, 129–144.
Jacob, D. J., 1986, Chemistry of OH in remote clouds and its role in the production of formic acid and peroxymonosulphate, J. Geophys. Res. 91, 9807–9826.
Jacob, D. J. and Wofsy, S. C., 1988, Photochemistry of biogenic emission over the Amazon forest, J. Geophys. Res. 93, 1477–1486.
Kelly, N. A., Wolff, G. T., and Ferman, M. A., 1984, Sources and sinks of ozone in rural areas, Atmos. Environ. 18, 1251–1266.
Madronich, S. and Calvert, J. G., 1990, Permutation reactions of organic peroxy radicals in the troposphere, J. Geophys. Res. 95D, 5697–5715.
Octavio, K. H., Arrocha, A., and Sanhueza, E., 1987, Low dispersion capacity of nocturnal Venezuelan savannah atmosphere, Tellus 39B, 286–293.
Sanhueza, E., Cuenca, G., Gomez, M. J., Herrera, R., Ishizaki, Ch., Marti, I., and Paolini, J., 1988, Characterization of the Venezuelan environment and its potential for acidification, in H. Rodhe and R. Herrera (eds.), Acidification in Tropical Countries, SCOPE series No. 36, Wiley, Chichester, pp. 197–255.
Sanhueza, E., Elbert, W., Rondon, A., Arias, M. C. and Hermoso, M., 1989, Organic and inorganic acids in rain from a remote site of the Venezuelan savannah, Tellus 41B, 170–176.
Sanhueza, E., Hao, W. M., Scharffe, D., Donoso, L., and Crutzen, P. J., 1990, N2O and NO emissions from soils of the northern part of the Guayana shield, Venezuela, J. Geophys. Res. 95D, 22481–22488.
Talbot, R. W., Beecher, K. M., Harris, R. C., and Cofer, W. R. III, 1988, Atmospheric geochemistry of formic and acetic acids at a midlatitude temperate site, J. Geophys. Res. 93, 1638–1652.
Talbot, R. W., Andreae, M. O., Berresheim, H., Jacob, D. J., and Beecher, K. M., 1990, Sources and sinks of formic, acetic and pyruvic acids over central Amazonia, J. Geophys. Res. 95, 16799–16811.
Wesely, M. L., 1989, Parameterization of surface resistance to gaseous dry deposition in regional-scale numerical models, Atmos. Environ. 23, 1293–1304.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Hartmann, W.R., Santana, M., Hermoso, M. et al. Diurnal cycles of formic and acetic acids in the northern part of the Guayana shield, Venezuela. J Atmos Chem 13, 63–72 (1991). https://doi.org/10.1007/BF00048100
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00048100