Atmospheric transport of pollutants from North America to the North Atlantic Ocean

Abstract

Ground-based measurements strongly support the hypothesis that pollutant materials of anthropogenic origin are being trans ported over long distances in the mid-troposphere and are a significant source of acid rain, acid snow, trace metal deposition, ozone and visibility-reducing aerosols in remote oceanic and polar regions of the Northern Hemisphere^1–4 Atmospheric sulphur budget calculatons⁵ and studies of acid rain on Bermuda⁶ indicate that a large fraction of pollutant materials emitted into the atmosphere in eastern North America are adverted eastwards over the North Atlantic Ocean. We report here the first direct airborne measurements of the vertical distribution of tropospheric aerosols over the western North Atlantic. A newly developed airborne differential adsorption lidar (DIAL) system⁷ was used to obtain continuous, remotely sensed aerosol distributions along its flight path. Our data document two episodes of long-distance transport of pollutant materials from North America over the North Atlantic Ocean.