The Penlee Point Atmospheric Observatory (PPAO) was established by the Plymouth Marine Laboratory in May 2014 for long term observations of ocean-atmosphere interaction. The observatory is only a few tens of metres away from the water edge and 11m above mean sea level.

At the mouth of the Plymouth Sound, the site (50° 19.08' N, 4° 11.35' W) is exposed to marine air when the wind comes from 110° - 240°. Typical southwesterly winds tend to bring relatively clean background Atlantic air. In contrast, winds from the southeast are often contaminated by exhaust plumes from passing ships. The PPAO is in close proximity to marine sampling stations that form the Western Channel Observatory, enabling better understanding of the ocean-atmosphere coupling.