Do anthropogenic, continental or coastal aerosol sources impact on a marine aerosol signature at mace head?

• Main Authors: O'Dowd, C., Ceburnis, D., Ovadnevaite, J., Vaishya, A., Rinaldi, M., Facchini, M. C.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Copernicus GmbH 2014
• Subjects: black carbon measurements; sea spray aerosol; boundary-layer; north-atlantic; atmospheric sulfur; light-scattering; organic aerosol; salt-sulfate; particles; submicron; Mace; North Atlantic
• Online Access: http://hdl.handle.net/10379/13232; https://doi.org/10.13025/26871; https://doi.org/10.5194/acp-14-10687-2014

Atmospheric aerosols have been sampled and characterised at the Mace Head north-east (NE) Atlantic atmospheric research station since 1958, with many interesting phenomena being discovered. However, with the range of new discoveries and scientific advances, there has been a range of concomitant criticisms challenging the representativeness of aerosol sampled at the station compared to that of aerosol over the pristine open-ocean. Two recurring criticisms relate to the lack of representativeness due to potentially enhanced coastal sources, possibly leading to artificially high values of aerosol concentrations, and to the influence of long-range transport of anthropogenic or continental aerosol and its potential dominance over, or perturbation of, a natural marine aerosol signal. Here, we review the results of previous experimental studies on marine aerosols over the NE Atlantic and at Mace Head with the aim of evaluating their representativeness relative to that of a pristine open-ocean aerosol, i.e. with negligible anthropogenic/continental influence. Particular focus is given to submicron organic matter (OM) aerosol. In summary, no correlation was found between OM and black carbon (BC) in marine air conforming to clean-air sampling criteria, either at BC levels of 0-15 or 15-50 ng m(-3), suggesting that OM concentrations, up to observed peak values of 3.8 mu g m(-3), are predominantly natural in origin. Sophisticated carbon isotope analysis and aerosol mass spectral finger printing techniques corroborate the conclusion that there is a predominant natural source of OM, with 80% biogenic source apportionment being observed for general clean-air conditions, rising to similar to 98% during specific primary marine organic plumes when peak OM mass concentrations > 3 mu g m(-3) are observed. Similarly, a maximum contribution of 20% OM mass coming from non-marine sources was established by dual carbon isotope analysis. Further, analysis of a series of experiments conducted at Mace Head conclude that negligible ...