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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Water-soluble ions species of size-resolved aerosols: Implications for the atmospheric acidity in Sao Paulo megacity, Brazil

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Vieira-Filho, Marcelo ; Pedrotti, Jairo J. ; Fornaro, Adalgiza
Total Authors: 3
Document type: Journal article
Source: ATMOSPHERIC RESEARCH; v. 181, p. 281-287, NOV 15 2016.
Web of Science Citations: 5

Over the last decade, an increase of ammonium salts in atmospheric deposition has been reported worldwide, especially in megacities. The present study aims to give a better comprehension analysis about particulate matter acidity in Sao Paulo megacity (MASP), Brazil. Size-resolved aerosols were sampled in MASP, during 2012 winter, showing a bimodal mass concentration distribution, with sulfate concentration exceeding 3.40 mu g m(-3), which accounted for over 25% of PM0.56 mass. Regarding the relative distribution of ionic species, 90% of NH4+ levels, were restricted to smaller than 1 mu m diameter range. The average neutralization index for PM < 1 mu m was 0.62, which indicated an ammonia-limiting atmosphere due to partial neutralization of atmospheric acids. Particles of the accumulation mode presented more acid behavior than other aerosol fractions, with pH value as low as 4.15 in PM0.56 The total neutralization index registered the lowest value for PM0.56, but it did not respond promptly to aerosol variations as the E-AIM model predictions. The highest discrepancies between the acidity proxies occurred in the smaller fractions of particulate matter, especially in the after-filter (AF) stage (diameter < 0.020 mu m). In addition, AF stage had the highest contribution to PM total mass, about 14% for all the stages analyzed. Such contribution indicates that acidity in ultrafine particles are still mixed for the MASP and need further investigation. (C) 2016 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 08/58104-8 - Narrowing the uncertainties on aerosol and climate changes in São Paulo State: NUANCES-SPS
Grantee:Maria de Fátima Andrade
Support type: Research Program on Global Climate Change - Thematic Grants