Ozone depletion nitrous oxide emissions over the natural background, which would in turn result in an increase in the amount of NO in the stratosphere. Thus human activity could affect the stratospheric ozone layer. In the following year, Crutzen and (independently) Harold Johnston suggested that NO emissions from supersonic passenger aircraft, which would fly in the lower stratosphere, could also deplete the ozone layer. However, more recent analysis in 1995 by David W. Fahey, an atmospheric scientist at the National Oceanic and Atmospheric Administration, found that the drop in ozone would be from 1–2 percent if a fleet of 500 supersonic passenger
Atmosphere of Venus and the upper one between 73–95 km. In the first layer the temperature is nearly constant at 230 K (−43 °C). This layer coincides with the upper cloud deck. In the second layer temperature starts to decrease again reaching about 165 K (−108 °C) at the altitude of 95 km, where mesopause begins. It is the coldest part of the Venusian dayside atmosphere. In the dayside mesopause, which serves as a boundary between the mesophere and thermosphere and is located between 95–120 km, temperature increases to a constant—about 300–400 K (27–127 °C)—value prevalent in the thermosphere. In contrast, the nightside