For the monitoring of emissions from the production of soda ash and sodium bicarbonate, the operator shall use a mass balance in accordance with Article 25. For emissions from combustion processes, the operator may choose to include them in the mass balance or to use the standard methodology in accordance with Article 24 at least for a part of the source streams, avoiding any gaps or double counting of emissions.

Where CO₂ from the production of soda ash is used for the production of sodium bicarbonate, the amount of CO₂ used for producing sodium bicarbonate from soda ash shall be considered as emitted by the installation producing the CO₂.