The Qinshan nuclear power plant (NPP) is one of China's nuclear power bases. An atmospheric experiment concerning siting of Qinshan NPP phase II is outlined and described. Hourly meteorological data were taken for 1 yr (from October 31, 1991 to October 31, 1992) at five different heights of a 100-m-high tower. Observations using a low-altitude radiosonde and a lost balloon were made for 40 days at three sites to measure the variance of turbulence at different heights and different distances from the coast. The diffusion parameters of the phase II site were measured using photographs of the plume and flight tests of the balance balloon. A wind tunnel simulation test was done to modify the influence of buildings on the diffusion parameters under D stable conditions. Synchronous low-altitude-wind, temperature, and surface-wind-field observations were made at three sites (phases I, II, and III) during September and October 1995 to provide a basic date for siting phase III. A method to estimate the annual atmospheric dispersion factor for a new site (phase III) using the available 1 yr of hourly meteorological observation data for an operating NPP (phase I) based on a meteorological correlation experiment is presented.