TY - JOUR
T1 - Mixing states of Amazon basin aerosol particles transported over long distances using transmission electron microscopy
AU - Adachi, Kouji
AU - Oshima, Naga
AU - Gong, Zhaoheng
AU - De Sá, Suzane
AU - Bateman, Adam P.
AU - Martin, Scot T.
AU - De Brito, Joel F.
AU - Artaxo, Paulo
AU - Cirino, Glauber G.
AU - Iii, Arthur J.Sedlacek
AU - Buseck, Peter R.
N1 - Funding Information:
Acknowledgements. Kouji Adachi and Naga Oshima thank the support of the Environment Research and Technology Development Fund (JPMEERF20165005, JPMEERF20172003, JP-MEERF20202003, and JPMEERF20205001) of the Environmental Restoration and Conservation Agency of Japan, the Global Environmental Research Coordination System from the Ministry of the Environment, Japan, and the Japan Society for the Promotion of Science (JSPS) KAKENHI (grant numbers JP25740008, JP26701004, JP16K16188, 16H01772, JP18H04134, JP18H03363, JP19H01972, JP19H04236, JP19K21905, and JP19H04259). Institutional support was provided by the Central Office of the Large Scale Biosphere Atmosphere Experiment in Amazonia (LBA), the National Institute of Amazonian Research (INPA), and Amazonas State University (UEA). We acknowledge the Atmospheric Radiation Measurement (ARM) Climate Research Facility, a user facility of the United States Department of Energy, Office of Science, sponsored by the Office of Biological and Environmental Research, and support from the Atmospheric System Research (ASR) program of that office. The research was conducted under scientific licenses 001030/2012-4, 001262/2012-2, and 00254/2013-9 of the Brazilian National Council for Scientific and Technological Development (CNPq). We acknowledge the use of imagery from the NASA Worldview application (https://worldview.earthdata.nasa.gov, last access: 20 October 2020), part of the NASA Earth Observing System Data and Information System (EOSDIS).
Funding Information:
Financial support. This research has been supported by the Environment Research and Technology Development Fund (grant nos. JPMEERF20165005, JPMEERF20172003, JPMEERF20202003, and JPMEERF20205001), the Global Environmental Research Coordination System, and the JSPS KAKENHI (grant nos. JP25740008, JP26701004, JP16K16188, JP16H01772, JP18H04134, JP18H03363, JP19H01972, JP19H04236, JP19K21905, and JP19H04259).
Publisher Copyright:
© 2020 Author(s).
PY - 2020/10/23
Y1 - 2020/10/23
N2 - The Amazon basin is important for understanding the global climate because of its carbon cycle and as a laboratory for obtaining basic knowledge of the continental background atmosphere. Aerosol particles play an important role in the climate and weather, and knowledge of their compositions and mixing states is necessary to understand their influence on the climate. For this study, we collected aerosol particles from the Amazon basin during the Green Ocean Amazon (GoAmazon2014/5) campaign (February to March 2014) at the T3 site, which is located about 70 km from Manaus, and analyzed them using transmission electron microscopy (TEM). TEM has better spatial resolution than other instruments, which enables us to analyze the occurrences of components that attach to or are embedded within other particles. Based on the TEM results of more than 10 000 particles from several transport events, this study shows the occurrences of individual particles including compositions, size distributions, number fractions, and possible sources of materials that mix with other particles. Aerosol particles during the wet season were from both natural sources such as the Amazon forest, Saharan desert, Atlantic Ocean, and African biomass burning and anthropogenic sources such as Manaus and local emissions. These particles mix together at an individual particle scale. The number fractions of mineral dust and sea-salt particles increased almost 3-fold when long-range transport (LRT) from the African continent occurred. Nearly 20 % of mineral dust and primary biological aerosol particles had attached sea salts on their surfaces. Sulfates were also internally mixed with sea-salt and mineral dust particles. The TEM element mapping images showed that several components with sizes of hundreds of nanometers from different sources commonly occur within individual LRT aerosol particles. We conclude that many aerosol particles from natural sources change their compositions by mixing during transport. The compositions and mixing states of these particles after emission result in changes in their hygroscopic and optical properties and should be considered when assessing their effects on climate.
AB - The Amazon basin is important for understanding the global climate because of its carbon cycle and as a laboratory for obtaining basic knowledge of the continental background atmosphere. Aerosol particles play an important role in the climate and weather, and knowledge of their compositions and mixing states is necessary to understand their influence on the climate. For this study, we collected aerosol particles from the Amazon basin during the Green Ocean Amazon (GoAmazon2014/5) campaign (February to March 2014) at the T3 site, which is located about 70 km from Manaus, and analyzed them using transmission electron microscopy (TEM). TEM has better spatial resolution than other instruments, which enables us to analyze the occurrences of components that attach to or are embedded within other particles. Based on the TEM results of more than 10 000 particles from several transport events, this study shows the occurrences of individual particles including compositions, size distributions, number fractions, and possible sources of materials that mix with other particles. Aerosol particles during the wet season were from both natural sources such as the Amazon forest, Saharan desert, Atlantic Ocean, and African biomass burning and anthropogenic sources such as Manaus and local emissions. These particles mix together at an individual particle scale. The number fractions of mineral dust and sea-salt particles increased almost 3-fold when long-range transport (LRT) from the African continent occurred. Nearly 20 % of mineral dust and primary biological aerosol particles had attached sea salts on their surfaces. Sulfates were also internally mixed with sea-salt and mineral dust particles. The TEM element mapping images showed that several components with sizes of hundreds of nanometers from different sources commonly occur within individual LRT aerosol particles. We conclude that many aerosol particles from natural sources change their compositions by mixing during transport. The compositions and mixing states of these particles after emission result in changes in their hygroscopic and optical properties and should be considered when assessing their effects on climate.
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U2 - 10.5194/acp-20-11923-2020
DO - 10.5194/acp-20-11923-2020
M3 - Article
AN - SCOPUS:85094915463
SN - 1680-7316
VL - 20
SP - 11923
EP - 11939
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
IS - 20
ER -