Dehumidified airveying of hygroscopic chemicals from storage to processing areas becomes critical in the pharmaceutical industry. Also, critical is the prevention of moisture regain when airveying, moisture-sensitive products to filling and packaging operations. The final packaged material must maintain its validity during the expected shelf life. The product package must maintain the "as manufactured" moisture level considering that air is packed with the product in the final step. Hence the cessity to surround the packaging area with dry air.