A heavy metal which in New Zealand comes mainly from burning timber treated with preservative copper-chromate-arsenic.  Arsenic can be emitted into the air by burning offcuts of treated timber from building projects for home heating.  Some industrial processes also emit arsenic.  Arsenic is a contaminant that can be toxic to people and animals if concentrations are too high.

View factsheets on Air Quality pollutants and Estuary contaminants