Emission of pesticides into the air

During and after the application of a pesticide in agriculture, a substanti al fraction of the dosage may enter the atmosphere and be transported over varying distances downwind of the target. The rate and extent of the emissi on during application, predominantly as spray particle drift, depends prima rily on the application method (equipment and technique), the formulation a nd environmental conditions, whereas the emission after application depends primarily on the properties of the pesticide, soils, crops and environment al conditions. The fraction of the dosage that misses the target area may b e high in some cases and more experimental data on this loss term are neede d for various application types and weather conditions. Such data are neces sary to test spray drift models, and for further model development and veri fication as well. Following application, the emission of soil fumigants and soil incorporated pesticides into the air can be measured and computed wit h reasonable accuracy, but further model development is needed to improve t he reliability of the model predictions. For soil surface applied pesticide s reliable measurement methods are available, but there is not yet a reliab le model. Further model development is required which must be verified by f ield experiments. Few data are available on pesticide volatilization from p lants and more field experiments are also needed to study the fate processe s on the plants. Once this information is available, a model needs to be de veloped to predict the volatilization of pesticides from plants, which, aga in, should be verified with field measurements. For regional emission estim ates, a link between data on the temporal and spatial pesticide use and a g eographical information system for crops and soils with their characteristi cs is needed.