NOx (Nitrogen Oxides)
Nitrogen oxides (NO and NO₂) formed during high-temperature gas combustion, a monitored pollutant that low-NOx burners are designed to limit.
What is NOx?
NOx covers the nitrogen oxides — mainly nitric oxide (NO) and nitrogen dioxide (NO₂) — produced during gas combustion. They form mostly through the thermal path: at the high temperature of a flame, the nitrogen and oxygen present in the combustion air combine to create these compounds.
Why monitor NOx?
NOx is a regulated air pollutant, which makes keeping it in check important when operating commercial heating equipment. Its level depends heavily on how the gas burner is tuned: flame temperature, excess air and air-gas mixing quality all directly influence how much is formed.
How is NOx formation reduced?
The main strategy is to lower the peak flame temperature — for example with a low-NOx burner, air staging or flue gas recirculation. Verification relies on a combustion analysis, which measures NOx among other parameters to confirm the tuning stays in line with the manufacturer’s instructions and applicable requirements.