Distribution of a tracer gas in a naturally ventilated greenhouse. measurements and simulations for pesticides dispersion determination

Numerical and experimental results concerning the emission of a tracer gas (N2O) inside a naturally ventilatedgreenhouse are presented and analyzed. Air sampleswere continuously taken at six points in the greenhouseand in two positions outside the greenhouse using two infrared gas analysers with multiple inlets. The calculationsby the numerical model were done for several wind directions and wind speeds. In each set values for the experiments were used for air speed and direction. The comparison between experimental data and simulationresults has shown a quantitatively and qualitatively good agreement, since, for the tested cases, the correlationcoefficients between measured and numerically obtainedvalues were varied between 0.81 and 0.985. The simulation results provided useful information about the emission of N2O around the experimental greenhouseand are a first step towards the determination of the behaviour of pesticides around greenhouses, since a similar behaviour should be expected when instead of N2O, a pesticide is used.