PFT

The PerFluorocarbon Tracer (PFT) method is a low-cost approach commonly used for measuring air exchange in buildings using tracer gases. It is a specific application of the more general Continuous-Injection, Long-Term Sampling (CILTS) method. The technique is widely used but there has been little work on understanding the uncertainties (both precision and bias) associated with its use, particularly given that it is typically deployed by untrained or lightly trained people to minimize experimental costs.

High local concentrations of a pollutant can be the result of high local emission rates of the pollutant orinsufficient ventilation. Using tracer gases to map the ventilation in multi-zone buildings combined withmeasurements of the local pollutant concentration provide the means to discriminate between thesecauses.

Portugal has technical recommendations and standards regarding ventilation rates in naturalventilation systems.