Any one of the less common gases found in the Earth’s atmosphere. Nitrogen, oxygen and argon make up more than 99% of the Earth’s atmosphere. Other gases, such as carbon dioxide, water vapor, methane, oxides of nitrogen, ozone and ammonia are considered trace gases.
Total primary energy supply per capita is a common, albeit imperfect, measure of energy efficiency in a country. Total Primary Energy Supply per Capita refers to the Total Primary Energy Supply (TPES) per head of population. The ratio is expressed in tons of oil equivalent (toe) per person. TPES consists of primary energy production adjusted for net trade and stock changes. Production of secondary energy (e.g. oil/coal products, electricity from fossil fuels, etc.) is not included since the “energy equivalent” of the primary fuels used to create the secondary products or electric power has already been counted. TPES is expressed in tons of oil equivalent. > >
A key petrochemical and an organic solvent; along with xylene, a key component in unleaded gasoline
