ISO 16000-26:2012 specifies the planning of carbon dioxide indoor pollution measurements. In the case of indoor air measurements, the careful planning of sampling and the entire measurement strategy are of particular significance since the result of the measurement can have far-reaching consequences, for example, with regard to ascertaining the need for remedial action or the success of such an action. An inappropriate measurement strategy can lead to misrepresentation of the true conditions or, worse, to erroneous results. ISO 16000-26:2012 is not applicable to the measurement strategy for carbon monoxide (CO).