LEVELS OF SPECIFIC AIR POLLUTANTS CHARACTERIZED BY ANNOYING ODOUR

In 2005, specific air pollutants hydrogen sulphide, mercaptans and ammonia (H2S, NH3, R-SH) were monitored in the area where Zagreb central water purification facility could affect ambient air quality and included one month of measurements for each season. Daily samples of hydrogen sulphide, mercaptans, ammonia and meteorological parameters (temperature, relative humidity, pressure and wind direction) were collected at four measuring sites. Seasonal differences and influence levels were studied. The results show relatively low concentrations of mercaptans and ammonia at all measuring sites for every season. Hydrogen sulphide concentrations were higher in the summer and autumn measurement periods, reaching over the recommended limit values. Compounds of annoying odour such as H2S, NH3 and R-SH should not be present in ambient air in concentrations higher than their odour threshold in order to keep the quality of living on a satisfactory level. No significant differences were found between measuring sites considering air temperature, air pressure and relative humidity. The differences between measuring sites considering wind direction and velocity are probably due to the local topography.