VapourThe gaseous phase of liquids or solids at atmospheric temperature and pressure.
VentilationIn this guide, the movement of air between the inside and outside of a building usually through windows, doors and air vents built into the building’s walls or ceilings.
VisibilityA measurement of the ability to see and identify objects at different distances. Visibility reduction from air pollution is often due to the presence of sulphur and nitrogen oxides, as well as particulate matter.
Visibility Reducing Particles (VRP)Any particles in the atmosphere that obstruct the range of visibility.
VolatileAny substance that evaporates readily.
Volatile Organic Compounds (VOCs)Carbon-containing compounds that evaporate into the air (with a few exceptions). VOCs contribute to the formation of smog and/ or may themselves be toxic. VOCs often have an odour and some examples include gasoline, alcohol and the solvents used in paints
VolcanoA volcano is a rupture on the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. Erupting volcanoes can pose many hazards, not only in the immediate vicinity of the eruption but also other areas such as volcanic ash which can spread over long distances.