Polycyclic aromatic hydrocarbons (PAHs, n = 36) were measured in the gas and particle phases in the atmosphere and the dissolved and particle phases in the waters of the New York—New Jersey Harbor Estuary, USA, during a weeklong intensive field campaign in July 1998. Mean total (gas + particulate) phenanthrene and pyrene concentrations were 3.3 and 0.33 ng/m3, respectively, over Raritan Bay, and 14 and 1.1 ng/m3, respectively, over New York Harbor. Similar PAH profiles (p values < 0.01) in the atmospheric gas phase and the dissolved phase in water demonstrate the close coupling of the air and water compartments. Air—water exchange fluxes of PAHs estimated using shore-based air data lead to erroneous flux estimates when compared to those derived using over-water air samples. The gross absorptive air—water flux dominates atmospheric loadings (wet, dry particle, gas absorption) to the estuary for PAHs of molecular weight < 234 g/mol. Dry particle deposition is increasingly more important for the higher-molecular-weight, particle-bound PAH species. Gross volatilization dominates gross absorption for the majority of PAHs in the New York—New Jersey Harbor Estuary.