Scientists have found that the concentration of hydroxyl radical in the atmosphere is increasing, enhancing its ability to self-purify. This important discovery helps to better understand the fight against pollution and global warming.
Hydroxyl radical (OH) is a reactive compound that is formed in the air when exposed to sunlight. It plays a key role in cleaning the atmosphere by destroying harmful gases such as methane and carbon monoxide. Even though OH only exists for a fraction of a second, it manages to neutralize up to 90% of some pollutants.
For a long time, studying the hydroxyl radical was difficult due to its extremely low and variable concentration. Its formation depends on ultraviolet radiation, so OH levels vary depending on the time of year and day – most of it is in the summer and during the day. Previously, methyl chloroform was used for research, but after the Montreal Protocol banned it in 1987, scientists had to look for new methods.
Experts from the National Institute of Water and Atmospheric Research (NIWA), Victoria University of Wellington and other research centers have developed a new way to measure the concentration of hydroxyl radical. They used radiocarbon monoxide (14CO), which is formed by cosmic rays and destroyed by OH. An analysis of 33 years of data from New Zealand and Antarctic stations showed that since 1997, the ability of the atmosphere to self-purify in the Southern Hemisphere has been increasing.
According to scientists, the level of 14CO in New Zealand decreases by 12% annually, and in Antarctica by 43% (but only in summer). This indicates an increase in the concentration of hydroxyl radical. Researchers have identified three main factors influencing this process:
– Increased emissions of nitrogen oxides (due to human activities).
– Destruction of the ozone layer.
– Increase in the amount of water vapor due to global warming.
Moreover, the more methane in the atmosphere, the less OH, which creates a complex relationship.
Without the hydroxyl radical, global warming would be much greater, since methane is a powerful greenhouse gas. New data is helping to better predict climate change and understand how human activity affects atmospheric chemistry.
Source: geonews.ru
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