It was found in concentrations of 29 to 850 pico grammes per cubic metre of air. A micro gramme is one trillionth of a gramme.

每立方空气中含有29到850微微克浓度。一微微克是一克的万亿分之一。

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Brief exposure to high levels of PCBs and dioxins may cause skin lesions and affect the liver (the tolerated daily intake for dioxin is about 1 picogram - one trillionth of a gram - per kg body weight).

CNN: THE GREAT DIOXIN SCARE