In an unprecedented study on the composition of bioaerosols in the Southern Ocean, researchers from Colorado State University have identified an atmospheric region that remains unchanged by human activity.
Weather and climate are closely linked, connecting every part of the world to other regions. As the climate changes rapidly due to human activity, scientists and researchers are struggling to find a corner of the Earth unaffected by humans.
However, Professor Sonia Kreidenweis and her team suspected that the air over the Southern Ocean would be the least affected by humans and the dust of continents.
Researchers discovered that the air in the boundary layer, which feeds the lower clouds over the Southern Ocean, was free of aerosol particles produced by human activity- including the burning of fossil fuels, the planting of certain crops, the production of fertilizers and the disposal of waste water - or transported from other countries of the world.
Air pollution is caused by aerosols, which are solid and liquid particles and gases suspended in the air.
The researchers decided to study what was in the air and where it came from using bacteria in the air as a diagnostic tool to deduce the properties of the lower atmosphere.
Thomas Hill researcher and co-author explained that "the aerosols controlling the properties of SW (Southern Ocean) clouds are strongly linked to ocean biological processes, and that Antarctica appears to be isolated southward dispersal of microorganisms and nutrient deposits from southern continents, "he said in a statement.
"Overall, this suggests that SW is one of the very few places on Earth that has been very little affected by human activities," he added.
Scientists sampled the air at sea limits - the part of the atmosphere that is in direct contact with the ocean - on a research boat traveling south to the ice edge of the ocean. 'Antarctica from Tasmania, Australia. Scientists then examined the composition of airborne microbes, which are found in the atmosphere and are often dispersed thousands of kilometers by the wind.
Using DNA sequencing, tracking sources and turning back paths scientist and first author Jun Uetake discovered that the microbes came from the ocean.
From the bacterial composition of microbes, the researchers concluded that aerosols from distant land masses and human activities, such as pollution or soil emissions caused by land-use change, did not move south and in the air.
Scientists say the results show a striking difference from all other ocean studies in both the northern hemisphere and the subtropics, which revealed that most of the microbes originated from windward continents.
In the study, published Monday in the Proceedings of the journal of the National Academy of Sciences, the scientists described the region as "really virgin".
Air pollution is already a global public health crisis and kills seven million people each year, according to the World Health Organization (WHO).
Studies have shown that air pollution increases the risk of heart disease, stroke and lung cancer.
More than 80% of people living in urban areas who monitor air pollution are exposed to air quality levels that exceed limits set by the WHO, the health organization said, and countries to low and middle income suffer the highest exposures.
However, as studies have shown, air pollution can cross geographic boundaries and affect people hundreds of kilometers from its origin.
