Perfluorocarbons (PFCs), PFCS
Perfluorocarbons (PFCs) are man-made compounds containing just fluorine and carbon. They are generally colourless, odourless non-flammable gases at environmental temperatures and for the most part chemically un-reactive.
Usage of PFCs is mainly in the electronics sector in semiconductor manufacture, however there is also significant usage as refrigerants (mainly in blends with HFCs and HCFCs). There is also some minor use as environmental tracer gases, in some fire extinguishing systems and in certain cosmetics and medical applications.
The major release is from primary aluminium production. The semiconductor industry is a relatively minor source and there are other small emissions from the refrigeration sector (leakage during operation and at the end of life destruction of equipment) and fire extinguishing systems.
Excessive exposure to perfluorocarbons may cause effects on the brain and heart. The main environmental concern with PFCs is the role these compounds play as greenhouse gases, influencing climate change. Consequently PFCs are controlled under the Kyoto Protocol. The concept of Global Warming Potential provides a common scale to compare the relative ability of different gases to trap heat in the atmosphere. PFCs have extremely high global warming potentials (5,000 to 10,000 times that of carbon dioxide). However, because they are only released in relatively small amounts, their contribution to global warming is minor. Due to their stability they have very long atmospheric lifetimes (thousands of years).