The principal gases provided are nitrogen, oxygen, carbon dioxide, argon, hydrogen, helium and acetylene; although a huge variety of gases and mixtures are available in gas cylinders.
factories can produce all kinds of pollution (smoke, liquids and solids) depending
on the type of stuff being made.OIL: liquid hydrocarbon
fuel; a fossil
fuel (except for a liquid biofuel called biodiesel which is produced from
crops such as canola and oil palms). Some power stations and almost all transport
(cars, aircraft, ships, trucks, buses, military vehicles) depend totally on
oil for engines to work. Burning oil in engines produces CO2 and other poisonous