Physicochemical properties of aerosols over the northeast Atlantic: Evidence for wind-speed-related submicron sea-salt aerosol production

Journal Article · Wed Jan 20 04:00:00 EST 1993 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/92JD02302· OSTI ID:6919348

O'Dowd, C D; Smith, M H ^[1]

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1. Univ. of Manchester Institute of Science and Technology (United Kingdom)

Physicochemical characteristics of submicron aerosol particles over the Northeast Atlantic (63[degrees]N, 8[degrees]W) during October/November 1989 have been examined using a thermal analytical technique and are classified according 10 air mass origin. Aerosol associated with anthropogenically influenced air masses contained typically 80% sulphate particles by number, the remainder being soot carbon and sea salt. For Arctic air masses the contribution of sulphate to the total aerosol was reduced to around 65%, due to low concentrations relative 10 sea salt which is dependent on wind speed. In situations with clean maritime air and high wind speeds, sulphate aerosol accounted for less than 25% of the total accumulation mode particles, the remainder consisting predominantly of sea salt. Arctic air masses and clean maritime air during periods of high winds were consistently acidic with inferred molar ratios of NH[sub 4][sup +]/SO[sub 4][sup =] near 0.2. The continental and modified maritime aerosol encountered was found to have molar ratios of about 0.8. Soot carbon was present in all air masses to a similar degree (5-13%). In clean air masses, submicron sea salt aerosol concentrations showed a strong exponential increase with wind speed (correlation coefficients cc [ge] 0.8), down to a dry particle radius of 0.05 [mu]m. Under these clean air' conditions and high winds the sea salt aerosol dominated all particle sizes for r > 0.05 [mu]m and accounted for approximately 75% of the total concentration, suggesting that under these conditions, sea salt aerosol would comprise the primary source cloud condensation nuclei (CCN) in stratiform clouds. 30 refs., 8 figs., 4 tabs.

• OSTI ID: 6919348
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 98:D1; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
AEROSOL MONITORING
AEROSOLS
AIR POLLUTION MONITORING
ATLANTIC OCEAN
CARBON
CHEMICAL PROPERTIES
CLOUDS
COLLOIDS
CONDENSATION NUCLEI
DISPERSIONS
ECOLOGICAL CONCENTRATION
ELEMENTS
MONITORING
NONMETALS
SEAS
SOLS
SOOT
SURFACE WATERS
WIND