The Italian Almanac

sun on snow

Italian Science - December 30

Sun on snow purifies the air above it, Italian scientists have found after research at the North and South Poles. The scientists from the National Research Council's Institute on Environmental Pollution (Iia) said that, with enough sun, certain compounds in ground snow released types of beneficial radicals that act as powerful oxidizing agents on all the substances around - including air pollutants.

"These results indicate that precipitation is not the terminal act in the removal of pollutants in the atmosphere but also come into play in the extremely complex chemical and physical processes of the atmosphere, in an unexpected way," said Iia lead researcher Ivo Allegrini.

The main active agents in this process are two compounds of nitrogen, nitric oxide (NO) and nitrous oxide (N2H), Allegrini said. The beneficial action of nitrous oxide is paradoxical because at certain concentrations it becomes a dangerous toxic substance, he added. In mountainous, snow-covered areas, on the other hand, "the substance turns out to be very useful - a further demonstration of the multivalency of processes that happen in the atmosphere".