For combustion to occur, oxygen must be present. Ammonium nitrate prills provide a much more concentrated supply of oxygen than the air around us.
Australia has ratified an agreement to phase out hydrofluorocarbons, a manmade compound once hailed as the saviour of the ozone layer. What went wrong?
While the gases most responsible for global warming - carbon dioxide, methane and nitrous oxide - continue to climb, other industrial greenhouse gases are being brought gradually under control.