6. Emission inventoryPollutants
What is basically measured is the emissions of the substances or substance classes sulphur dioxide (SO2
), nitrogen oxide (NOx
), carbon monoxide (CO), organic compounds and dusts.
Sulphur dioxide is almost exclusively the result of combustion processes with fossil energy sources like fuel and coal. Sulphur dioxide is a colourless gas, which is smelt or tasted by people as from a concentration of 0.8 to 2.6 mg/mÂ³. Due to its high water solubility, the gas is rapidly transformed into sulphurous acid.
Nitrogen oxides are produced during practically all combustion processes: first through oxidation of nitrogen in the air in very high temperatures, second from organic nitrogen compounds in fossil fuels. Traffic is the major source of this pollutant. Nitrogen monoxide (NO) and nitrogen dioxide (NO2
) are referred to as nitrogen oxides (NOx
). More than 90 % of all nitrogen oxides occurs as NO, a colourless, odourless and tasteless gas, which is rapidly oxidized in the air into NO2
is a reddish-brown gas with a sharp and biting odour.
Carbon monoxide is another corrosive gas typical of traffic as about 2/3 of the total CO emissions are produced during the combustion of petrol in car engines. Carbon monoxide is colourless, odourless and tasteless and is produced during incomplete combustion of carbon and its compounds.
The concentration of dust particles is influenced to a high degree by coal firing but also by industry (in the field of iron and steel) and the handling of dusty goods. The term dust means particles which can be found in different sizes and concentrations in the air.
Organic compounds is the umbrella term for a variety of substances (hydrocarbons and other carbon compounds). This is why they cannot be allocated to a particular source group. While power stations only account for a small amount of these emissions, the pollutant concentration in cities derives practically equally from the sources industry, trade and domestic fuel as well as traffic. The sector of solvents of all kinds plays a major part in this pollutant group. Pollution from agricultural activities must be considered in rural areas as well. There are so many hydrocarbons that the analysis is only restricted by the sensitivity and selectivity of the applied methods.
|© City of Stuttgart, Office for Environmental Protection, Section of Urban Climatology