The downside of summer sunshine

The June heatwave brought dangerously high ozone levels and caused serious summer smog

The hottest June day in the UK since 1976 caused widespread summertime smog across southern England and the Midlands. Sevenoaks in Kent and Lullington Heath, East Sussex, measured the greatest ozone level for 11 years; reaching eight on the UK government's ten-point scale for the first time. The winds then turned westerly and carried our polluted air eastwards to create problems over Germany.

Ozone can take days to form in the atmosphere. It therefore spreads across very wide areas. To reduce the worst impacts, Paris once again banned the oldest vehicles from its roads and, in a targeted approach, restrictions were placed on industries that emit volatile hydrocarbons that contribute to ozone formation. In a re-run of the 2003 heatwave, smoke from the tragic forest fires in Portugal spread over France and reached the UK during the hot weather.