NOx Emission Calculator

Estimating a Pollutant That Forms From the Air Itself

Unlike CO2 and SO2, NOx doesn't come primarily from fuel content — a meaningful share forms from atmospheric nitrogen reacting at high flame temperature. Emission factors capture this temperature-dependent behavior empirically.

The Formula

NOx Mass = Heat Input(GJ) × NOx Emission Factor(g/GJ)

Typical factors run 40-60 g/GJ for well-tuned natural gas burners (default 50), higher for oil and coal.

Worked Example

A process with 500 GJ of heat input at 50 g/GJ:

NOx = 500 × 50 = 25,000 g = 25 kg

How to Use This Calculator

Enter the total Heat Input in GJ.
Optionally adjust the NOx Emission Factor (defaults to 50 g/GJ).
Select Calculate to get NOx mass emitted.

Related Calculations

Need CO emissions too? See the CO Emission Calculator, or check the flame temperature driving thermal NOx in the Adiabatic Flame Temperature Calculator.