Search results for "Atmospheric concentrations"
showing 4 items of 4 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…
Particle size distributions of currently used pesticides in ambient air of an agricultural Mediterranean area
2014
This work presents first data on the particle size distribution of 16 pesticides currently used in Mediterranean agriculture in the atmosphere. Particulate matter air samples were collected using a cascade impactor distributed into four size fractions in a rural site of Valencia Region, during July to September in 2012 and from May to. July in 2013. A total of 16 pesticides were detected, including six fungicides, seven insecticides and three herbicides. The total concentrations in the particulate phase (TSP: Total Suspended Particulate) ranged from 3.5 to 383.1 pg m(-3). Most of the pesticides (such as carbendazim, tebuconazole, chlorpyrifos-ethyl and chlorpyrifos-methyl) were accumulated …
Particle size distributions of currently used pesticides in a rural atmosphere of France
2013
This work presents first data on the particle size distributions of current-used pesticides in the atmosphere. Ambient air samples were collected using a cascade impactor distributed into four size fractions in a rural site of Centre Region (France). Most pesticides were accumulated in the fine (0.1-1 mu m) particle size fraction such as cyprodinil, pendimethalin, fenpropidin, fenpropimorph and spiroxamine. Other pesticides such as acetochlor and metolachlor presented a bimodal distribution with maximum concentrations in the ultrafine (0.03-0.1 mu m) coarse (1-10 mu m) and in the ultrafine fine size ranges, respectively. No pesticides were detected in the size fraction >10 mu m. (C) 2013 El…