Tracing the mysterious filter of the atmosphere

Nature uses a substance capable of destroying pollutants to clean the air, but so far humans have not found this substance.

Many scientists believe that the atmosphere of the earth is capable of self-cleaning. Some previous studies have shown that gas and contaminants at the lowest level in the atmosphere are decomposed by molecules that are called hydroxyl (OH) radicals.

OH (highly reactive) roots are continuously regenerated in the atmosphere by reactions with water vapor and nitrous oxide - two substances that exist in the air. Those reactions break down contaminants. Therefore, this process can be considered a self-cleaning mechanism of nature. But when the OH radical is regenerated by nitrous oxide, the reaction will produce ozone gas - a toxic substance that can cause a greenhouse effect. Thus, if a place with a lot of OH origin, the ozone concentration there is also high.

One corner of the Pearl River Delta region, China.Photo: mep.gov.cn.

But when it came to the Pearl River Delta (China), scientists of Geosphere Institute of Chemistry and Dynamics (Germany) discovered the opposite. Here the OH root is concentrated in a denser density all over the world in an area of ​​about 60 square kilometers, but the concentration of ozone in the air is very low.

'That is what shocked us. After many years of research, until now we have witnessed such a paradoxical phenomenon, ' said Franz Rohrer, an expert at the Geosphere Institute of Chemistry and Dynamics.

The findings suggest that there is still one more natural substance to regenerate OH radicals without the need for nitrous oxide. But so far the scientific world has not had the right equipment to detect it.

Andreas Hofzumahaus, an expert at the Geosphere Institute of Chemistry and Dynamics, plans to simulate processes in the Pearl River Delta atmosphere in the laboratory to find the mysterious substance. If you do that, humans will have new tools to clean the atmosphere.

'We are lucky because harmful contaminants decompose very quickly. But unfortunately, the process of removing pollutants creates ozone. If we find that mysterious substance, we will enjoy two benefits , 'Hofzumahaus commented.