The hydrogen sulphide (H(2)S) and sulphur dioxide (SO(2)) data from Kalevi air quality monitoring station in the town of Kohtla-Jarve, the centre of Estonian oil shale processing industry, and some episodic measurements from a nearby location, are analysed in view of wind direction and other meteorological parameters governing the atmospheric dispersion. Unlike in a typical urban airshed, sulphur compounds in Kohtla-Jarve constitute a major air quality problem, H(2)S sometimes exceeding the permitted limit value. At Kalevi monitoring station two narrow wind direction intervals are identified as related to high concentrations. According to time-dependent pattern and wind direction analysis at different heights, these two peaks are most likely originating from the oil-shale retorting plant and the Kohtla-Jarve municipal wastewater treatment plant. Due to active reconstructions of these plants, both concentration peaks have been decreased during recent years.