MOUNTAINEERS climbing Mount Everest will have to battle with a cloak of ozone that descends over the peak as the day wears on.
During expeditions to Everest in the summer of 2001 and 2002, Tong Zhu from Peking University in Beijing, China, and his colleagues measured ozone and carbon monoxide levels at an altitude of 5000 metres. Taking readings every minute for a week they saw a daily ozone cycle, starting at around 40 parts per billion in the early morning and rising to around 80 ppb by midday, remaining high until midnight (Geophysical Research Letters, DOI: 10.1029/2006GL027726).
The…
