| Zdroj: |
Glasius, M, Wessel, S, Christensen, C S, Jacobsen, J K, Jørgensen, H E, Klitgård, K C, Petersen, L, Rasmussen, J K, Hansen, T S & Lohse, C 2000, ' Sources to formic acid studied by carbon isotopic analysis and air mass characterization ', Atmospheric Environment, vol. 34, pp. 2471-79 . https://doi.org/10.1016/s1352-2310(99)00416-1 |
| Popis: |
The carbon isotopic composition of formic acid samples from a rural and a semi-remote area in Denmark has been investigated by collection of 5–6 day integrated samples during winter and spring. The results show that 80–100% of formic acid stems from biogenic VOC emitted from terrestrial sources. Even during winter there is a dominating biogenic contribution, which is surprising since biogenic emissions are very low at these latitudes in that period. Quality assurance samples have been used to check the reliability of the collection and pre-treatment procedures for atmospheric formic acid samples. The carbon isotopic investigation was supplemented by measurements of benzene, toluene, formaldehyde, acetone, acetaldehyde and nitrogen dioxide in order to characterise the air masses of one formic acid sample. The general air mass analysis showed that the sampling site, a semi-remote area, was without significant local air pollution sources. During the formic acid sampling period, the air masses were influenced by both direct anthropogenic emissions (benzene, toluene, nitrogen dioxide and acetone) and compounds formed during long-range transport of anthropogenic hydrocarbons (formaldehyde and acetaldehyde). Nevertheless, formic acid still had a predominantly (89±5%) biogenic origin. |
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