Long-range transported air pollution has markedly decreased in Ireland and Europe over the last two decades. Yearly average nss-sulphate concentration has dropped by 70% at Mace Head during the last decade alone. Backward air mass trajectories indicated little contact with the North American continent precluding significant transport of anthropogenic particulate matter in an increasingly cleaner atmosphere. Polluted easterly air masses from the European continent rarely reach as far as the mid North Atlantic, making the eastern North Atlantic one the cleanest regions in the Northern Hemisphere. Carbon isotope analysis  has confirmed the above findings also for carbonaceous particulate matter. The influence of natural biogenic components including biogenic non-sea-salt sulphate and sea salt is having increasing impact on air quality and cloudiness with significant climatic implications.