Compound

Concentration

N₂

70 - 75 (V/V)%

CO₂

5 - 25 (V/V)%

H₂O

9 - 14 (V/V)%

O₂

0.7 - 10 (V/V)%

SO₂

0 - 1500 ppm

CO

50 - 150 ppm

Dust

100 - 800 ppm

Heavy metals

0.05 - 0.5 ppm