Even the finest particles of pollution influence the process of cloud formation and the rainfall regime. A study conducted in Manaus, the capital of Amazonas state in Brazil’s North region, shows that oxidation leads small aerosols expelled by factories and car exhausts, for example, to grow very rapidly, reaching up to 400 times their original size, and that this affects raindrop formation.
Even the finest particles of pollution influence the process of cloud formation and the rainfall regime. A study conducted in Manaus, the capital of Amazonas state in Brazil’s North region, shows that oxidation leads small aerosols expelled by factories and car exhausts, for example, to grow very rapidly, reaching up to 400 times their original size, and that this affects raindrop formation.
“Understanding cloud and rain formation mechanisms in the Amazon is a major challenge because of the complexity of the non-linear physical and chemical processes that occur in the atmosphere,” said Paulo Artaxo, a professor at the University of São Paulo’s Physics Institute (IF-USP) and penultimate author of an article on the study published in Science Advances.
The co-authors are all researchers affiliated with institutions in the United States, except Artaxo and Luiz Augusto Machado, also a professor at IF-USP.
The discovery enhances the accuracy of climate change studies based on mathematical models and simulations. “These nanoparticles of pollution [smaller than 10 nanometers] used to be overlooked in atmospheric calculations and models. The focus was on particles larger than 100 nm because these act as cloud condensation nuclei [on which water vapor condenses to form droplets] and change the rainfall regime. This study shows that smaller particles oxidize as they travel through the atmosphere, expanding rapidly until they reach the size necessary to become condensation nuclei,” Machado said.
The data was collected by instruments on board a special aircraft that flew over the Manaus pollution plume for about 100 kilometers (km) in 2014 and 2015 during the Green Ocean Amazon (GOAmazon) scientific campaign. FAPESP funded the study via its support for the campaign and a Thematic Project, in both cases under the aegis of the FAPESP Research Program on Global Climate Change (RPGCC).
Read more at: Fundacao de Amparo A Pesquisa do Estado de Sao Paulo
Researchers have found that nanoparticles resulting from human activities such as the burning of fossil fuels rapidly grow in the atmosphere and influence cloud formation. (Photo Credit: Luiz Augusto Machado)
