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Summer Smog Story Board

This is a series of pictures with accompanying text which explains how summer smog (ozone) can be formed in a large coastal city.

	Narrative: In summer photo-chemical smog can start to form in a city when there is a layer of stable air above the ground known as an inversion.
	This inversion layer can act like a lid, trapping air pollutants below it.
	From about 6 am, motor vehicles release pollutants, such as various oxides of nitrogen, and hydrocarbons, into the air.
	As the ground warms up, these pollutants rise into the atmosphere, but are trapped under the inversion layer.
	For coastal cities, an offshore breeze may move the cocktail of pollutants over the water ...
	...where they remain concentrated below the inversion layer.
	During the course of the day, sunlight and high temperatures can make the chemicals react to form ozone - a gas harmful to humans, animals and plants.
	In the afternoon a sea breeze can bring the "cooked" pollutants back towards the city,...
	...firstly hitting the bayside suburbs, and if the breeze is strong enough, the suburbs further inland.

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The contents of this page were last edited, Monday, 17 July 2006

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