A preparation intended to produce immunity to a disease by stimulating the production of antibodies.


The gaseous phase of substances that are liquid or solid at atmospheric temperature and pressure, e.g., steam.

Vapor capture system

Any combination of hoods and ventilation system that captures or contains organic vapors so that they may be directed to an abatement or recovery device.


1. An organism, often an insect or rodent, that carries disease. 

2. An object (e.g., plasmids, viruses or other bacteria) used to transport genes into a host cell. A gene is placed in the vector; the vector then “infects” the bacterium.


cycle track; cycleway; contrasts with freeway.


Vermicomposting is the process of having redworms and other decomposer organisms process our organic waste and turn it into a great natural fertilizer.

Very Dense Forest
Lands with forest cover having a canopy density of 70 percent and above.


type of plastic (usually PVC) used to make products such as fruit juice bottles, credit cards, pipes and hoses.

Vinyl chloride

A chemical compound used in producing some plastics that is believed to be carcinogenic.

Virtual water

The volume of water required to produce a commodity or service. First coined by Professor J.A. Allan of the University of London in the early 1990s, though this is now more widely known as cf. embedded (embodied) water.

Visual waste audit

Visual waste audit - Observing, estimating and recording data on waste streams and practices without physical weighing.


Description of any substance that evaporates readily.

Volatile organic compound

Molecules containing carbon and differing proportions of other elements such as hydrogen, oxygen, fluorine and chlorine. With sunlight and heat they form ground-level ozone

The degree of loss to a given element or set of elements within the area affected by a hazard. It is expressed on a scale of 0 (no loss) to 1 (total loss). Also, a set of conditions and processes resulting from physical, social, economic, and environmental factors, which increase the susceptibility of a community to the impact of hazards.