Irish Meteorological Society

John Finnan
Environmental Protection Agency

Ozone is a naturally occurring gas found throughout the atmosphere. Approximately 90% of atmospheric ozone is found in the stratrosphere where ozone is most concentrated in a layer at the top of the stratrosphere known as the ozone layer. Ozone is a strong absorber of UV radiation and the ozone layer acts to shield the earth from harmful UV radiation from the sun. The remaining 10% of atmospheric ozone is found in the troposphere. Ozone is formed in the troposphere when sunlight acts on a mixture of hydrocarbons and oxides of nitrogen, these ozone precursors are naturally emitted from plants and soil respectively. Levels of tropospheric ozone may also increase when stratrospheric ozone migrates down to the earth's surface. Anthropogenic emissions of hydrocarbons and nitrogen oxides have led to a doubling of concentrations of tropospheric ozone in the last century and ozone levels continue to rise. Ozone is a strong oxidant, reacting easily with many substances and can cause damage to materials, plants and crops as well as to human beings, ozone is also an important greenhouse gas. An ozone monitoring network was established in Ireland in 1992 to monitor ground level ozone and to provide warning to the public of high ozone concentrations. High ozone concentrations are typically recorded in Ireland when anticyclonic conditions provide h! igh levels of sunshine and advect ozone precursors from the European mainland, the two essential prerequisites for ozone formation.

Room G32 Earlsfort Terrace, NUI Dublin

8p.m. Thursday 16th September, 2004

Members of the Public are Welcome to Attend
Updated Fri 3 Sep 2004