Measurements of the aerosol particle size, aerosol volume distribution and aerosol volatility (diameter range 0.1-3.0 mu m), aerosol mass (diameter range 0.06-16.0 mu m), condensation nuclei (CN) and cloud condensation nuclei (CCN), and black carbon (BC) mass concentration at Mace Head during the EU project ''Background Maritime Contribution to Atmospheric Pollution in Europe'' (BMCAPE), obtained over four intensive campaigns during the period between November 1993 and August 1994, are presented. Marine air was found to possess mean accumulation mode (ACM) aerosol particle number concentration., N, of between 100 and 160 cm(-3) for the winter and summer seasons. Marine ACM mass ranged in value from about 0.8 to 6 mu g m(-3). Marine air was found to contain black carbon with episodic mean mass concentrations generally in the range 5-40 ng m(-3). The impact of black carbon on the marine environment is also reflected by the moderately positive correlation (r(2) in the range 0.23-0.44) found between marine ACM number concentration and BC mass loading, with a higher correlation (r(2) = 0.55) found for winter continental air. Black carbon accounted for between 0.6% and 1.2% of the ACM mass loading for marine aerosol at Mace Head, increasing to between 4% and 6% for continental air. Arithmetic mean values of ACM number concentration N and BC mass concentration agree quite well with results from a few other investigators of marine atmospheric aerosol in the North Atlantic. (C) 1997 Elsevier Science Ltd.