World Pollutionwatch: Fire can kill – far from the flames

Vancouver is normally one of the world's cleanest cities but this July its air resembled that in Beijing due to smoke and ash from forest fires over 200 kilometres away. Further fires along the western side of the US and Canada have caused numerous health warnings especially at night when smoke settled on valley communities. During August hot weather across southern Europe also led to forest fires in Spain, Portugal and Greece.

Related: Pollutionwatch: The world's dirtiest cities