HOW are the main pollutants formed in vehicle engines and what environmental problems do they cause?
1. Nitrogen oxides (NOx), such as nitrous oxide and nitrogen dioxide are formed by reaction of nitrogen with oxygen in the air used during combustion. NOx forms nitric acid or nitrous acid that will contribute to acid rain. 2. A range of sulphur oxides (SOx) are formed by reaction of sulphur impurities (or maybe additives) in the fuel with oxygen in the air SOx will form sulphuric or sulphurous acid that will also contribute to acid rain. 3. Carbon monoxide formed by partial combustion of the hydrocarbon fuel and is poisonous. 4. Soot, is essentially small carbon particles that are formed by incomplete combustion of the fuel and have been implicated in contributing to lung diseases as well as turning everything black. 5. Carbon dioxide formed by combustion of the fuel and is a greenhouse gas. 6. Unburnt hydrocarbons may also be greenhouse gases. 7. Polyaromatic hydrocarbons are probably formed by a range of reactions, possibly including aromatic fuel additives and are very toxic.
