Fossil fuel percent of [its] weighted emissions in 1998. Combustion of fossil fuels also produces other air pollutants, such as nitrogen oxides, sulfur dioxide, volatile organic compounds and heavy metals. According to Environment Canada: "The electricity sector is unique among industrial sectors in its very large contribution to emissions associated with nearly all air issues. Electricity generation produces a large share of Canadian nitrogen oxides and sulphur dioxide emissions, which contribute to smog and acid rain and the formation of fine particulate matter. It is the largest uncontrolled industrial source of mercury emissions in Canada. Fossil fuel-fired electric power plants also emit
Lower sulfur oxides Lower sulfur oxides The lower sulfur oxides are a group of inorganic compounds with the formula SO, where m < 2n. These species are often unstable and thus rarely encountered in everyday life. They are significant intermediates in the combustion of elemental sulfur. Some well characterized examples include sulfur monoxide (SO), its dimer SO, and a series of cyclic sulfur oxides, SOx (x = 1, 2), based on cyclic S rings. Interest in the lower sulfur oxides has increased because of the need to understand terrestrial atmospheric sulfur pollution and the finding that the extraterrestrial atmospheres of Io, one of