PAH
Polynuclear Aromatic Hydrocarbons.

Parameter
A quantity or quality that can be measured.

PCB
Polychlorinated biphenyls.

PCDD & PCDF
Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans. (see dioxins)

Peer Review
Review by one or more professionals in the field.

PID
Photo-Ionisation Detector.

Plume Dispersion Modelling
Computer models which are used to predict ground level concentrations of pollutants emitted from release points.

Pollution
Direct or indirect introduction of a substance, physical - chemical or biological factor, which causes undesirable modifications in the ecosystems, causing a negative effect on mankind and other species.

Protocol
Operational procedures for a particular site used in testing work.

PTFE
Polytetrafluoroethylene.

PUF
Polyurethane Foam.