The ozone layer was up to 30 per cent thinner over Europe during the first week of February and periodic depletions like this are becoming more frequent, say scientists at the European Space Agency (ESA).
The Global Ozone Monitoring Experiment (GOME) is mounted on ESA鈥檚 ERS-2 satellite and has a spectrometer that measures UV radiation in the 240 to 790 nanometre region. Ozone has a signature peak at 325 to 335 nm.
鈥淥ver the last five years we have seen more of these ozone thinning episodes,鈥� says Diego Loyola from DLR, the German aerospace centre. 鈥淏ut we have only been monitoring since 1995 and we would need at least 20 years鈥� worth of data to draw a firm conclusion.鈥�
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The thinning resulted from streamers of tropical air from the equatorial regions 鈥� where ozone levels are lower 鈥� spreading up across southern Spain, France and Germany, decreasing the total ozone coverage.
Harmful rays
Coverage levels of below 250 Dobson units were seen 鈥� an ozone hole is classed as coverage below 200 Dobson units. The decreased ozone means an increased amount of harmful radiation from the Sun reaches people on the ground.
But Jonathan Shanklin, from the British Antarctic Survey and one of the team that discovered the Antarctic ozone hole, said that these low levels are not unusual and they have been much lower.
鈥淭hey don鈥檛 last for more than a few days and they are just one-tenth the size of the hole in Antarctica. But on clear days we are exposed to dangerous levels of UV rays,鈥� Shanklin told New 杏吧原创.