HR: 1330h
AN: A32A-0127    [PDF]
TI: Atmospheric Behavior of Inorganic Water-Soluble Gas and Aerosol Species at a Rural Site in the Amazon Basin
AU: * Trebs, I
EM: ivonne@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Biogeochemistry Department, J.J.v. Becherweg 27, Mainz, 55128 Germany
AU: Meixner, F X
EM: meixner@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Biogeochemistry Department, J.J.v. Becherweg 27, Mainz, 55128 Germany
AU: Slanina, J
EM: slanina@ecn.nl
AF: Energy Research Centre of the Netherlands, Department of Air Quality, ZG Petten, Petten, 1755 Netherlands
AU: Moura, M A
EM: malm@ccen.ufal.br
AF: Universidad Federal de Alagoas, Departamento de Meteorologia, Centro de Ciencia Exatas e Naturais, Tabuleiro dos Martins, Maceio, Alagoas, 57072-970 Brazil
AU: da Silva, R S
EM: malm@ccen.ufal.br
AF: Universidad Federal de Alagoas, Departamento de Meteorologia, Centro de Ciencia Exatas e Naturais, Tabuleiro dos Martins, Maceio, Alagoas, 57072-970 Brazil
AU: Artaxo, P
EM: artaxo@if.usp.br
AF: Instituto de Fˇsica, Universidad de Sao Paulo, Rua do Matao, Travessa R, 187, Sao Paulo, 05508-900 Brazil
AU: Andreae, M O
EM: andreae@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Biogeochemistry Department, J.J.v. Becherweg 27, Mainz, 55128 Germany
AB: We investigated diel and seasonal variations of ammonia (NH$_{3}$), nitric acid (HNO$_{3}$), nitrous acid (HONO), hydrochloric acid (HCl) and the water-soluble inorganic aerosol species, ammonium (NH$_{4}^{+}$), nitrate (NO$_{3}^{-}$), nitrite (NO$_{2}^{-}$), chloride (Cl$^{-}$) and sulfate (SO$_{4}^{2-}$) on a pasture site in the Amazon Basin (Rond\^{o}nia, Brazil) from September to November 2002 (LBA-SMOCC). Measurements were performed on-line using a wet-annular denuder in combination with a Steam-Jet Aerosol Collector (SJAC) supported by monitoring of meteorological quantities (e.g., relative humidity, air temperature, wind speed). Widespread biomass burning resulted in a significant enhancement of soluble trace gas levels, of which ammonia showed the highest abundance. We found a strong dependence of ammonia, nitric acid, and aerosol ammonium nitrate on meteorological parameters (especially air temperature and relative humidity) as well as on boundary layer conditions during day and nighttime. Deposition of soluble gases on wet surfaces at night was promoted by the increase of relative humidity to nearly 100 %. Obviously, re-evaporation of ammonia and nitric acid contributed effectively to increased mixing ratios in the turbulent boundary layer at daytime. Additionally, our measurements support the assumption of a continuous HONO source since a complete depletion at daytime was not found. Under clean conditions (wet season), HONO photolysis at daytime was very low and it is expected that its contribution to OH radical production was most likely small compared to the dry season (biomass burning). Our results provide important information about gas-aerosol interactions in a tropical region and the influence of meteorological parameters on emission and deposition processes of inorganic water-soluble species under biomass burning and clean conditions.
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0315 Biosphere/atmosphere interactions
DE: 0322 Constituent sources and sinks
DE: 0345 Pollution--urban and regional (0305)
DE: 0394 Instruments and techniques
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting