Search results for " atmospheric concentrations"
showing 2 items of 2 documents
The Odonatoptera of the Late Permian Lodève Basin (Insecta).
2008
8 pages; International audience; The discovery of numerous and very diverse Odonatoptera in the Red Late Permian Lodève Basin questions its current reconstructions of a dry to very dry palaeoclimate and palaeoenvironment. It rather suggests the presence of more or less permanent water bodies, surrounded by a diversity of terrestrial biotas. The discovery of large to very large Meganeuridae contradicts the alleged relations between the decrease of body and wing sizes of the insects during the late Permian as a direct consequence of the decrease of the oxygen atmospheric concentrations at that time.
Measurements of Hg0 (and H2S) at the Solfatara Crater (Southern Italy): Estimating the atmospheric distribution with a real-time approach
2015
Volcanic and geothermal areas are important emitters of natural gas compounds into the atmosphere, which can be of concern when discharging close to densely, populated sites. Mercury has a strong environmental impact, its organic and inorganic complexes being toxic. The dominant form of Hg in the atmosphere is gaseous elemental mercury (GEM), which has high volatility and residence time of 1-2 years. Volcanic degassing accounts for a significant part of the natural mercury emissions. No mercury limits or target values in ambient air are present in the EU legislations, whereas US-EPA and ATSDR impose 300 and 200 ng/m3, respectively, as a limit for chronic exposure. WHO has proposed the annua…