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Industry is not the big contributor to air pollution in this
region. Our biggest polluters are motor vehicles and domestic
fires.
Vehicles account for 94% of the nitrogen oxides in the region’s
air, 78% of the carbon monoxide and 45% of the carbon dioxide,
which is also a major problem for our climate (see below).
In winter, domestic fires are the main problem, particularly in
the Wairarapa, Upper Hutt and Wainuiomata which are affected by
cold, calm conditions when ‘temperature inversions’ occur.
In winter, very rapid cooling of the earth after nightfall
results in a layer of cold air being trapped by warmer air above.
Air pollutants from cars and domestic fires also get trapped in the
cold layer. With nowhere to go, especially in valleys surrounded by
hills, these pollutants can build up to potentially harmful
levels.
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