Ozon#

Ozone, triatomic form (O3) of oxygen, colourless, highly reactive gas with a pungent odour. Prolonged exposure to abnormally high concentrations of ozone can cause eye and airway irritations in human beings and damage to plants. Ozone monitoring on the basis of uniform standards has been carried out at 120 measuring points throughout Austria since 1989. The Ozone Act (Law Gazette (BGBl) 210/1992) requires ozone concentration monitoring throughout the territory of Austria and stipulates threshold values (three-hour averages): Early warning stage at 0,2 mg/m3, warning stage 1 at 0,3 mg/m3 and warning stage 2 at 0,4 mg/m3. In northern and eastern Austria the early warning stage is reached on up to 20 days a year, in the rest of Austria only occasionally.