… reduced in small, fixed percentage steps until the WHO recommendations are met at urban background stations – an average annual pollution level of 5 µg/m³ for PM 2.5 …

… by 5 to 16 tropical nights is to be expected. In the Upper Rhine Rift Valley and in urban agglomerations, the greatest increase in tropical nights is to be expected. By … by 5 to 16 tropical nights is to be expected. In the Upper Rhine Rift Valley and in urban agglomerations, the greatest increase in tropical nights is to be expected. By …