In 2020, the world's carbon dioxide emission was 31.98 billion tons, a decrease of 2.056 billion tons compared with 2019, a year-on-year decrease of 6.04%. In 2020, China's carbon dioxide emissions accounted for 30.93% of the world's total carbon dioxide emissions, accounting for the largest proportion. Carbon dioxide carbon dioxide, a carbon oxide compound, is a colorless, odorless or colorless gas with a slight sour taste in its aqueous solution under normal temperature and pressure.
Carbon dioxide is mainly used to refrigerate perishable food (solid), as refrigerant (liquid), manufacture carbonated soft drinks (gaseous) and solvents for homogeneous reaction (supercritical state), etc.
In terms of physical properties, the melting point of carbon dioxide is - 56.6 ℃ (527kpa), the boiling point is - 78.5 ℃, the density is higher than that of air (under standard conditions), and it is soluble in water. （ErYangHuaTanPaiFangZhanShiJieZongLiang）