However, Professor Sonia Kreidenweis and her team suspected that the air over the Southern Ocean would be the least affected by humans and dust from the world’s continents.
The researchers found that the air in the boundary layer, which feeds the lowest 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 elimination of wastewater, or transportation from other countries in the world.
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 infer the properties of the lower atmosphere.
Scientific researcher and study co-author Thomas Hill explained that “the aerosols that control the properties of SO (Southern Ocean) clouds are strongly linked to oceanic biological processes, and that Antarctica seems to be isolated from the dispersion of microorganisms towards the and the deposition of nutrients from southern continents, “he said in a statement.
“Overall, it suggests that SO is one of the few places on Earth that has been minimally affected by anthropogenic activities,” he added.
Scientists sampled air at the level of the marine limit, the part of the atmosphere that has direct contact with the ocean, aboard a research ship that travels south to the edge of Antarctic ice from Tasmania, Australia. Scientists then examined the composition of microbes in the air, found in the atmosphere and often dispersed thousands of kilometers by the wind.
Using DNA sequencing, source tracking, and backtracking trajectories, scientist and first author Jun Uetake He discovered that the origins of microbes were from the ocean.
From the bacterial composition of the microbes, the researchers concluded that aerosols from distant land masses and human activities, such as pollution or emissions from the soil caused by the change in land use, did not travel south. and into the air.
Scientists say the results show a big difference from all other ocean studies in both the northern and subtropical hemispheres, which found that most microbes came from upwind continents.
Air pollution is already a global public health crisis and kills seven million people each year, according to the World Health Organization (WHO).
More than 80% of people living in urban areas that monitor air pollution are exposed to air quality levels that exceed the limits of WHO guidelines, the health organization said, and low-income countries and Mediums suffer the highest exposures.