Combustion of Fuels and Nitrogen Oxides (NO_x) Emission

Emission of Nitrogen Oxides - NO_x - with combustion of fuels like oil, coal, propane and more

  Emission of Nitrogen Oxides - NO_x - when burning fuels:

Fuel	Emission of NOx 1) (g/kg fuel)
Oil	3.0
Kerosene	3.0
Coal	4.5
Propane	2.3
Gasoline	27 3)
Hydrogen	0 2)
Natural Gas	1.0
Butane	2.3
Wood, Birch 20% moisture content	0.7

¹⁾ note that the emission varies widely depending on application temperatures and air/fuel ratios. In general - higher combustion temperature and  higher air/fuel ratios increases NO_x emissions.
²⁾ zero emission for hydrogen is a theoretically value. In practice hydrogen burned in air produces more NO_x than natural gas due to the high flame speed
3) catalytic systems common on most modern vehicles reduces NO_x
NO_x emissions contributes to eutrophication, acidification and the formation of ground-level ozone.