A new study led by Colorado State University professor Sonia Kreidenweis and published in the Proceedings of the National Academy of Sciences (PNAS) shows that when measuring the Southern Ocean south of 40° south latitude, Studying the composition of bioaerosols, they discovered the cleanest air on Earth.
Weather and climate are complex processes related to human activities, and due to rapid climate changes caused by human activities, it is difficult to find any area or process on the earth without human influence. Credenweis and her team suspect that the air over the remote Southern Ocean, which surrounds Antarctica, is least affected by humans and dust from the continent.
Researchers are using bacteria in the air above the Southern Ocean as diagnostic tools to infer key properties of the lower atmosphere. They sampled the ocean boundary layer air on a research vessel traveling from Tasmania to the edge of the Antarctic ice. These atmospheres are filled with microorganisms that are dispersed hundreds to thousands of kilometers around by the wind.
Through DNA sequencing, source tracking and return air trajectories, the researchers determined that these microorganisms originated from the ocean. The analysis found that the bacterial composition came from a broad latitude band, suggesting that distant terrestrial aerosols and human activities did not enter Antarctic air southward.
The researchers said they strictly controlled harsh laboratory conditions during the experiment to ensure that the air was not polluted. Through analysis, it was found that the air over the Southern Ocean is very clean, with almost no DNA available for research. It can be said to be the cleanest air on earth.