Glossary beginning with P
- PCB (Polychlorinated Biphenyls)
group of extremely stable chemical compounds with excellent dielectric and heat transfer properties, widely used in the past in both the industrial and commercial sectors (e.g., in capacitors and transformers). Because of their toxicity to humans and to the environment, PCBs are among the most dangerous pollutants.
- PM (Particulate Matter)
category of particles, solids and liquids with a diameter ranging from a few nanometers (nm) to a few tens or hundreds of micrometers (μm). Their physical and chemical properties allow them to remain suspended in the atmosphere for long periods (hours, days or years), retaining their physical and/or chemical reactivity as distinct entities.