SOx NOx Emission Calculator

Work out sox nox emission instantly with clear inputs, formula shown and shareable results.

About SOx NOx Emission Calculator

Sulphur in fuel converts almost entirely to sulphur dioxide, so uncontrolled emissions are fuel mass times sulphur fraction times two — the molecular mass ratio of SO2 to S. Nitrogen oxides come from both fuel nitrogen and thermal fixation of air nitrogen, so they are estimated from an emission factor rather than fuel composition.

Formulas

Sulphur dioxide

SO2 (t) = fuel (t) x sulphur % x 2, reduced by control efficiency

Nitrogen oxides

NOx (t) = fuel (t) x NOx factor (kg/t) / 1000

Worked example

With the default values below, SOx NOx Emission Calculator returns Sulphur Dioxide Emitted of 4.800. Change any input above and every figure here is recalculated in your browser.

Inputs used

Fuel Consumedminimum 0 t/day: 5,000 t/day
Sulphur Contentaccepts 0–15 %: 0.6 %
NOx Emission Factorminimum 0 kg per tonne fuel: 4.5 kg per tonne fuel
Control Equipment Efficiencyaccepts 0–100 %: 92 %

Results

Sulphur Dioxide Emitted: 4.800
Uncontrolled Sulphur Dioxide: 60.000
Nitrogen Oxides Emitted: 5.940
Sulphur Dioxide Captured: 55.200

Step by step

1Values used
2Sulphur dioxide
3Nitrogen oxides
4Sulphur Dioxide Emitted= 4.800
5Uncontrolled Sulphur Dioxide= 60.000
6Nitrogen Oxides Emitted= 5.940
7Sulphur Dioxide Captured= 55.200

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Sulphur dioxide and nitrogen oxide emissions are subject to statutory limits and continuous monitoring requirements. Use the prescribed measurement and reporting methodology for compliance.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Sulphur dioxide and nitrogen oxide emissions are subject to statutory limits and continuous monitoring requirements. Use the prescribed measurement and reporting methodology for compliance.

Frequently Asked Questions

Why the factor of two for sulphur dioxide?

Sulphur has atomic mass 32 and sulphur dioxide 64, so every tonne of sulphur burnt yields two tonnes of sulphur dioxide.

How are nitrogen oxides controlled?

Combustion measures first — low-NOx burners, staged air, flue gas recirculation — then post-combustion selective catalytic or non-catalytic reduction, which can achieve 80-90% removal.