Experiments on sulphuric acid nucleation in low oxygen atmospheres were done in order to investigate the role of nucleation in the Archean atmosphere. Nucleation initiated by photolysis of SO2 and subsequent reaction between atomic O and SO2 was measured with a PSM and a separate CPC. The parameters were <10 ppm O2 with varying levels of SO2 (4 levels from 40 to 105 ppb), RH (3 levels from 0 to 51%), UV light (254 nm, 4 levels from 55 to 100% power), and ionization (2 levels: Background (∼3 cm−3 s−1) and increased w. gamma sources (∼42 cm−3 s−1)). We find that nucleation is possible under these conditions and that the measured formation rates correlate positively with all varied parameters. This suggests that the sulphuric acid nucleation system could have played a role in the Archean atmosphere.
Bibliographical noteFunding Information:
We thank Sebastian Danielache and Matthew S. Johnson for insightful conversations and help in understanding the sulphur chemistry. NJS thanks the generous support of the Israel Ministry of Energy . We thank the Kurt J. Lesker company for use of the drawing in Fig. 1 .
© 2022 The Author(s)
- Archean atmosphere
- Low oxygen
- Relative humidity
- Sulphuric acid