ABSTRACT
From the beginning of the industrial application of air separation by low temperatures, it was
obvious that contaminants such as water and carbon dioxide had to be eliminated. Later on,
it became painfully evident that from a safety point of view other dangerous hydrocarbons,
especially acetylene, also had to be removed. Present day list of dangerous contaminants that
may be found in the atmosphere of a highly industrial area is given in Table 5.1. The
concentrations indicated, however, are to be considered as a yearly average and not as
maximum. The project engineer should make a thorough study of the local atmospheric
conditions.
