IAQ UK is an independent organisation with the aim of 'raising the agenda of indoor air quality within the home and workplace'

IAQUK Resources - Definitions



Aromatics are hydrocarbons, organic compounds that consist exclusively of the elements carbon and  hydrogen. Are so called because of their distinctive perfumed smell and are substances derived from crude oil and, in small quantities, from coal.


A compound (or molecule) is a combination of two or more chemical elements (atoms) held together by chemical bonds.


Cumene Process

This process converts two relatively cheap starting materials, benzene and propylene, into acetone and phenol.

The process of boiling a liquid and condensing and collecting the vapour. This process is used to purify liquids and to separate liquid mixtures. In the oil industry, distillation is used to separate crude oil, which is a mixture of hydrocarbons with different boiling temperatures, into groups of hydrocarbons that have specified boiling points.


Dry distillation

The heating of solid materials to produce gaseous products which may condense into liquids or solids.



Elements are pure substances that are made out of just one kind of atom. The best way to know which pure substances are considered as elements is through looking at the Periodic Table.


Any of a class of organic compounds made from the chemical reaction between an alcohol and an organic acid.


An organic compound that consists exclusively of the elements carbon and hydrogen. Generally, the term hydrocarbon is used for the chemicals that are derived from natural gas, oil and coal.


Inorganic is said of any substance in which two or more chemical elements other than carbon are combined. Every chemical is either inorganic or organic.

Isomer / Isomeric 
Two or more substances that have identical molecular formulas but different molecular structures orconfigurations, and hence different properties, are called isomers. Isomers differ only in the arrangement of their component atoms.


Chemical combination of two or more atoms of the same chemical element (such as O2 - which is Oxygen) ordifferent chemical elements (such as H2O - which is water).


NVOC - Non-Volatile Organic Compound

Any organic compound not volatile enough to be detected as vapour-phase constituent of indoor air.


Organic chemicals 
Organic chemicals are based on carbon compounds and form the backbone of the petrochemicals industry, while inorganic chemicals are non-carbon chemicals, such as chlorine, alkalis or hydrogen peroxide. Every chemical is either organic or inorganic.


When certain individual molecules (monomers) come together and link up in a chain-like fashion they form a polymer. The chemical reaction that forms a polymer is called polymerisation. Polymers usually have high melting and boiling points. There are natural polymers such as DNA, and synthetic polymers, such as polystyrene and fibreglass.


POM - Particle-bound Organic Matter

Any organic compound not volatile enough to be detected as vapour-phase constituent of indoor air but that can be detected in solid form in indoor air - as small airborne particles, or adsorbed on inorganic dust particles.


SVOC - Semi-Volatile Organic Compound

Any organic compound less volatile than VOC.



The gas given off by substances that are solids or liquids at ordinary atmospheric pressure and temperatures.


VOC - Volatile organic compounds

An organic chemical compounds that have high enough vapor pressures under normal conditions to significantly vaporize and enter the earth's atmosphere.


VVOC - Very Volatile Organic Compound

Any organic compound more volatile than VOC.