Emergence of healing in the Antarctic ozone layer.

Industrial chlorofluorocarbons that cause ozone depletion have been phased out under the Montreal Protocol. A chemically driven increase in polar ozone (or "healing") is expected in response to this historic agreement. Observations and model calculations together indicate that healing of the Antarctic ozone layer has now begun to occur during the month of September.

Fundamental differences between Arctic and Antarctic ozone depletion.

Antarctic ozone depletion is associated with enhanced chlorine from anthropogenic chlorofluorocarbons and heterogeneous chemistry under cold conditions. The deep Antarctic "hole" contrasts with the generally weaker depletions observed in the warmer Arctic. An unusually cold Arctic stratospheric season occurred in 2011, raising the question of how the Arctic ozone chemistry in that year compares with others.

Nitrogen trifluoride global emissions estimated from updated atmospheric measurements.

Nitrogen trifluoride (NF(3)) has potential to make a growing contribution to the Earth's radiative budget; however, our understanding of its atmospheric burden and emission rates has been limited. Based on a revision of our previous calibration and using an expanded set of atmospheric measurements together with an atmospheric model and inverse method, we estimate that the global emissions of NF(3) in 2011 were 1.18 ± 0.

Automated measurement of nitrogen trifluoride in ambient air.

We present an analytical method for the in situ measurement of atmospheric nitrogen trifluoride (NF(3)), an anthropogenic gas with a 100-year global warming potential of over 16,000. This potent greenhouse gas has a rising atmospheric abundance due to its emission from a growing number of manufacturing processes and an expanding end-use market. Here we present a modified version of the "Medusa" preconcentration gas chromatography/mass spectrometry (GC/MS) system of Miller, B.