Experimental study about the influence of wind velocity and temperature on the emission rate of vocs from liquid surface

The characterization of passive liquid area sources for the study of Volatile Organic Compounds (VOCs) emission is a matter of great concern. The volatilization of these compounds is a complex phenomenon, being potentially affected by different chemical and physical parameters. In view of this, the present study aims to investigate the influence of wind velocity and temperature on the emission of VOCs from liquid surfaces. For the purpose of this study, the behaviour of acetone and butanol in solution with water are examined by varying some parameters inside a wind tunnel system. In particular, the wind velocity flowing through the device is varied in a range from 0.02 m/s to about 0.06 m/s and the temperature of the liquid source in a range from 20 °C to 35 °C. The obtained results show as the emission rate of these two compounds appears not to be significantly affect by the wind velocity. In view of this, the approach commonly suggested to take into account a dependence of the odour emission rate on the square root of the wind velocity appears to excessively overestimate the emission rate. On the contrary, the liquid temperature highly influences the emission phenomenon leading to an increase of one order of magnitude of the emission rate. This effect is more pronounced for butanol, consistently with the trend of several chemical-physical parameters governing the volatilization process as a function of temperature.