Letter: O
OECD Organization for Economic Co-operation and Development
OHSAS18001 An international certification standard relating to safety at work and industrial hygiene. This standard establishes the requisites for a Health and Safety at work management system, in order to allow companies to manage its liabilities in this respect and improve its performance in the field..
Organic solvent Any VOC (see entry) used alone or in combination with other agents in order to dissolve primary materials, products or waste materials, without being subject to chemical transformation, or used as cleaning agents to dissolve contaminants, or used as a solvent,a means of dispersion, a corrector of viscosity, as a corrector of surface tension, as a plasticizer or a preservative.
Ozone An allotropic form of oxygen with the chemical symbol O3. It is found in small quantities throughout the atmosphere and is formed by the action of electrical discharges and ultraviolet light that convert oxygen molecules into ozone. At around 25 km from the earth's surface there is a concentrated layer of ozone that absorbs ultraviolet rays and represents a vital shield (the ozonosphere). The diminution of the thickness of and creation of holes in the ozone layer appears to be linked to human activities releasing nitric oxides and chlorofluorocarbons (see entry) into the air.