Browsing by Author "Barraza, Francisco"
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- ItemAnthropogenic Perturbations to the Atmospheric Molybdenum Cycle(2021) Wong, Michelle Y.; Rathod, Sagar D.; Marino, Roxanne; Li, Longlei; Lambert, Fabrice; Howarth, Robert W.; Alastuey, Andres; Alaimo,Maria Grazia; Barraza, Francisco; Castro Carneiro, Manuel
- ItemCharacterizing the Atmospheric Mn Cycle and Its Impact on Terrestrial Biogeochemistry(2024) Lu, Louis; Li, Longlei; Rathod, Sagar; Hess, Peter; Martinez, Carmen; Fernandez, Nicole; Goodale, Christine; Thies, Janice; Wong, Michelle Y.; Alaimo, Maria Grazia; Artaxo, Paulo; Barraza, Francisco; Barreto, Africa; Beddows, David; Chellam, Shankarararman; Chen, Ying; Chuang, Patrick; Cohen, David D.; Dongarra, Gaetano; Gaston, Cassandra; Gomez, Dario; Morera-Gomez, Yasser; Hakola, Hannele; Hand, Jenny; Harrison, Roy; Hopke, Philip; Hueglin, Christoph; Kuang, Yuan-Wen; Kylloenen, Katriina; Lambert, Fabrice; Maenhaut, Willy; Martin, Randall; Paytan, Adina; Prospero, Joseph; Gonzalez, Yenny; Rodriguez, Sergio; Smichowski, Patricia; Varrica, Daniela; Walsh, Brenna; Weagle, Crystal; Xiao, Yi-Hua; Mahowald, NatalieThe role of manganese (Mn) in ecosystem carbon (C) biogeochemical cycling is gaining increasing attention. While soil Mn is mainly derived from bedrock, atmospheric deposition could be a major source of Mn to surface soils, with implications for soil C cycling. However, quantification of the atmospheric Mn cycle, which comprises emissions from natural (desert dust, sea salts, volcanoes, primary biogenic particles, and wildfires) and anthropogenic sources (e.g., industrialization and land-use change due to agriculture), transport, and deposition, remains uncertain. Here, we use compiled emission data sets for each identified source to model and quantify the atmospheric Mn cycle by combining an atmospheric model and in situ atmospheric concentration measurements. We estimated global emissions of atmospheric Mn in aerosols (<10 mu m in aerodynamic diameter) to be 1,400 Gg Mn year(-1). Approximately 31% of the emissions come from anthropogenic sources. Deposition of the anthropogenic Mn shortened Mn "pseudo" turnover times in 1-m-thick surface soils (ranging from 1,000 to over 10,000,000 years) by 1-2 orders of magnitude in industrialized regions. Such anthropogenic Mn inputs boosted the Mn-to-N ratio of the atmospheric deposition in non-desert dominated regions (between 5 x 10(-5) and 0.02) across industrialized areas, but that was still lower than soil Mn-to-N ratio by 1-3 orders of magnitude. Correlation analysis revealed a negative relationship between Mn deposition and topsoil C density across temperate and (sub)tropical forests, consisting with atmospheric Mn deposition enhancing carbon respiration as seen in in situ biogeochemical studies.
- ItemConstraining Present-Day Anthropogenic Total Iron Emissions Using Model and Observations(2024) Rathod, Sagar D.; Hamilton, Douglas S.; Nino, Lance; Kreidenweis, Sonia M.; Bian, Qijing; Mahowald, Natalie M.; Alastuey, Andres; Querol, Xavier; Paytan, Adina; Artaxo, Paulo; Herut, Barak; Gaston, Cassandra; Prospero, Joseph; Chellam, Shankararaman; Hueglin, Christoph; Varrica, Daniela; Dongarra, Gaetano; Cohen, David D.; Smichowski, Patricia; Gomez, Dario; Lambert, Fabrice; Barraza, Francisco; Bergametti, Gilles; Rodriguez, Sergio; Gonzalez-Ramos, Yenny; Hand, Jenny; Kyllonen, Katriina; Hakola, Hannele; Chuang, Patrick; Hopke, Philip K.; Harrison, Roy M.; Martin, Randall V.; Walsh, Brenna; Weagle, Crystal; Maenhaut, Willy; Morera-Gomez, Yasser; Chen, Yu-Cheng; Pierce, Jeffrey R.; Bond, Tami C.Iron emissions from human activities, such as oil combustion and smelting, affect the Earth's climate and marine ecosystems. These emissions are difficult to quantify accurately due to a lack of observations, particularly in remote ocean regions. In this study, we used long-term, near-source observations in areas with a dominance of anthropogenic iron emissions in various parts of the world to better estimate the total amount of anthropogenic iron emissions. We also used a statistical source apportionment method to identify the anthropogenic components and their sub-sources from bulk aerosol observations in the United States. We find that the estimates of anthropogenic iron emissions are within a factor of 3 in most regions compared to previous inventory estimates. Under- or overestimation varied by region and depended on the number of sites, interannual variability, and the statistical filter choice. Smelting-related iron emissions are overestimated by a factor of 1.5 in East Asia compared to previous estimates. More long-term iron observations and the consideration of the influence of dust and wildfires could help reduce the uncertainty in anthropogenic iron emissions estimates.
- ItemEvolution of air quality in Santiago : the role of mobility and lessons from the science-policy interface(2018) Gallardo, Laura; Barraza, Francisco; Ceballos, Andrés; Galleguillos, Mauricio; Huneeus, Nicolás; Lambert, Fabrice; Ibarra, Cecilia; Munizaga, Marcela A.; O'Ryan, Raúl E.; Osses, Mauricio; Tolvett, Sebastián; Urquiza, Anahí; Véliz, Karina D.
- ItemRelationship between Wildfire Smoke and Children’s Respiratory Health in the Metropolitan Cities of Central-Chile(2022) Ciciretti, Rebecca; Barraza, Francisco; Barrera, Francisco de la; Urquieta, Lorna; Cortés, Sandra; CEDEUS (Chile)
- ItemSource apportionment of ambient PM2.5 in Santiago, Chile: 1999 and 2004 results(ELSEVIER SCIENCE BV, 2012) Jorquera, Hector; Barraza, FranciscoA receptor model analysis has been applied to ambient PM2.5 measurements taken at Santiago, Chile (33.5 degrees S, 70.7 degrees W) in 2004 (117 samples) and in 1999 (95 samples) on a receptor site on the eastern side of the city. For both campaigns, six sources have been identified at Santiago and their contributions in 1999/2004 are: motor vehicles: 28 +/- 2.5/31.2 +/- 3.4%, wood burning: 24.8 +/- 2.3/28.9 +/- 3.3%, sulfates: 18.8 +/- 1.7/16.2 +/- 2.5%, marine aerosol: 13 +/- 2.1/9.9 +/- 1.5%, copper smelters: 11.5 +/- 1.4/9.7 +/- 3.3% and soil dust: 3.9 +/- 1.5/4.0 +/- 2.4%. Hence relative contributions are statistically the same but the absolute contributions have been reduced because ambient PM2.5 has decreased from 34.2 to 25.1 mu g/m(3) between 1999 and 2004 at Santiago. Similarity of results for both data sets - analyzed with different techniques at different laboratory facilities - shows that the analysis performed here is robust.
- ItemTraditional ethnobotanical knowledge and use of medicinal plants in a rural area of the metropolitan region of Chile: descriptive study(2014) Barraza, Francisco; Calvo, Carlos; Silva, Mauricio; Vinet, Raul; Laurido, Claudio; Barrera, Elizabeth; Meza, Ines; Vargas-Rueda, Silvia; Martinez, Jose L.In order to characterize and evaluate the botanical knowledge belonging to the population in rural area (little addressed by the ethnobotany) a study was conducted through surveys to learn about medicinal plants cultivated and used and a rural area of the Metropolitan Region (San Juan de Pirque). The conclusions are that users have a hybrid knowledge (product of traditional knowledge combined with information of various kinds) of medicinal plants. We found that most of the species cultivated in botanical gardens were species introduced and very few native ones. Also, they were known by their common names and new names were detected not described previously in the literature.