Source apportionment of atmospheric aerosol in a marine dusty environment by ionic/composition mass balance (IMB)

• Published in: Atmospheric chemistry and physics Vol. 18; no. 17; pp. 13215 - 13230
• Main Authors: Cardoso, Joao, Almeida, Susana M, Nunes, Teresa, Almeida-Silva, Marina, Cerqueira, Mario, Alves, Celia, Rocha, Fernando, Chaves, Paula, Reis, Miguel, Salvador, Pedro, Artinano, Begona, Pio, Casimiro
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 13-09-2018; Copernicus Publications
• Subjects: Aerosol particles; Aerosols; Ammonia; Analysis; Atmospheric aerosols; Atmospheric particulates; Composition; Distribution; Dust; Dust plumes; Dust storms; Environmental aspects; Inorganic compounds; Mass; Particulate matter; Plumes; Profiles; Salts; Soil; Cabo Verde
• ISSN: 1680-7324; 1680-7316; 1680-7324
• DOI: 10.5194/acp-18-13215-2018

PM10 aerosol was sampled in Santiago, the largest island of Cabo
Verde, for 1 year, and analysed for elements, ions and carbonaceous material.
Very high levels of dust were measured during the winter months, as a result
of the direct transport of dust plumes from the African continent. Ionic and
mass balances (IMBs) were applied to the analysed compounds, permitting the
determination of six to seven different processes and source contributions to
the aerosol loading: insoluble and soluble dust, sea salt, carbonaceous
material and secondary inorganic compounds resulting from the reaction of
acidic precursors with ammonia, sea salt and dust. The mass balance could be closed by
the consideration and estimation of sorbed water that constituted
20 %–30 % of the aerosol mass. The balance methodology was compared
with positive matrix factorisation (PMF), showing similar qualitative source
composition. In quantitative terms, while for soil dust and secondary
inorganic compound source classes, the results are similar, for other sources
such as sea-salt spray there are significant differences in periods of dust
episodes. The discrepancies between both approaches are interpreted based on
calculated source profiles. The joint utilisation of the two methodologies,
which are complementary, gives confidence in our capability for the correct
source apportionment of aerosol particles.