Carbon is contained in all organic compounds and has the property that carbon atoms can form chains of any length with each other. Many compounds of organic chemistry consist of the elements carbon and hydrogen and are called hydrocarbons. One atom of carbon can for example link with four atoms of hydrogen to form CH4 and is thus saturated.
The crosslinking of the C atoms in conjunction with the H atoms can be continued indefinitely in line with the general formula of the alcanes. The first members of this series are gaseous, the ones in the middle in the range of C5 - C16, on the other hand, are liquid, the higher ones solid.
Hydrocarbon Content of Air
Median-Day Values
Diagram 1.9.1
Saturated hydrocarbons are primarily obtained from mineral oil. Crude oil is processed in refineries. Here, distillation is used to fractionate the crude oil into constituents of differing boiling points and drawn off separately, ranging from petrol via kerosene to lubricating oil. When these substances are used, they are released into the environment. Diagram 1.9.1 shows the total hydrocarbon content.of atmospheric air, using a small town as an example. It is not only motor traffic which loads up the air with hydrocarbons. For instance, the metal working industry uses compounds based on hydrocarbons as lubricants and coolants.
Diagram 1.9.2
The high temperatures generated by metal cutting cause the coolant to evaporate and separate out hydrocarbons. Oil fog concentrations in the most varied production areas with a widely differing and in part high level are shown over the course of a day in diagram 1.9.2. The content of suspended dust in breathing air, which is relevant for assessing the oil content, amounts to average values of clearly less than typically 100 µm/m3 of air. For instance, the 267 measuring stations of the environmental authorities in the Federal Länder found dust suspension levels in the air of only 38 - 51 µm/m3 between the end of April and the beginning of May 1994, taking the average over the entire Federal Republic. However, these are only average mean values and can lead to false assessment when applied to particular compressed air stations.
