Abstract The use of an extensive system of ground based air quality monitoring units during the Nanticoke Environmental Study of May/June 1978 is described. Plume dispersion, rise, and ground level SO 2 concentrations were measured by COSPEC, LIDAR, mobile chemistry laboratories and a fixed network of SO 2 sensors. The experiment provided considerable detail on two specific coastal fumigation events from which shoreline dispersion models may be tested. A more general study of plume dispersion from the coastal power plant showed that, despite complications with the two stack nature of the source, rise and dispersion into the stable on-shore flow agree with existing theory. Dispersion within the thermal internal boundary layer is considerably enhanced.