INFORMATION AND ALERT THRESHOLDS
ANNEX XIISupplementary provisions
ANNEX XII INFORMATION AND ALERT THRESHOLDS A. Alert thresholds for pollutants other than ozone To be measured over three consecutive hours at locations representative of air quality over at least 100 km 2 or an entire zone or agglomeration, whichever is the smaller. Pollutant Alert threshold Sulphur dioxide 500 µg/m 3 Nitrogen dioxide 400 µg/m 3 B. Information and alert thresholds for ozone Purpose Averaging period Threshold Information 1 hour 180 µg/m 3 Alert 1 hour ( 1 ) 240 µg/m 3 ( 1 ) For the implementation of Article 24, the exceedance of the threshold is to be measured or predicted for three consecutive hours.