SPADA Draft Documents

performance of a biothreat agent detection method or system. If a soil is too moist, the 545 soil can be dried to a more acceptable moisture content by air drying with frequent 546 mixing in a sterile environment until the moisture content is low enough. Drying a soil is 547 not recommended unless the method or system being evaluated requires dryer soil. Avoid 548 collecting soil samples after a weather event in order to avoid overly moist soil. To add 549 moisture to a soil, sterilized water can be sprayed onto the soil while monitoring the 550 increase in mass by weighing the soil while spraying. Once added, mix the soil well to 551 ensure even distribution of the added moisture. 552 Soils should be kept in the dark and preferably in an incubator. The container lid 553 should be either opened regularly to ensure a consistent atmosphere or placed ajar with 554 sterile cloth over the container opening preventing contamination in a humidity- 555 controlled incubator. 556 If planning a time series experiment, either a large batch experiment or sacrificial 557 replicates can be used. During each sampled time point, the water content of the soil 558 should be measured as well in order to report the data in soil dry weight. 562 multiple environments and under multiple seasonal conditions. Typically, open-air field 563 testing is conducted using a truth box of ca. ½ km 2 in area. Multiple ground truth 564 instrumentation towers are placed within the box and used in conjunction with 565 meteorological instrumentation placed nearby at heights ranging from 1-3 meters. 566 Ground truth data typically include aerodynamic particle size, concentration, and 567 559 560 561 10.2 Outdoor Testing Set-up Field testing designed to simulate a biothreat agent release should be carried out in

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