Aerosol particles are one important key player in the Arctic climate. Using long-term measurements of particle light scattering from an observatory on Svalbard, this study investigates the reasons behind an observed shift towards larger particles seen in the last 2 decades. We find that increases in sea spray are the most likely cause. Air masses from the south-west have increased significantly, suggestive of a potential mechanism, whilst the retreat in sea ice has a marginal influence.