An adhesive substrate is affixed to the front of a ~ 1cm long, 3 mm diameter sample holder. The sample holder is inserted and secured at the front of a 3D printed bar, which retracts behind a 3D printed cap to protect the substrate when not sampling. The bar is actioned forward (sampling) or backward (protected) by a servo and lever mechanism (not shown in above figure). There will be two GPaC sampler on the UAV, one on each wing.
The autopilot and/or the pilot can activate the GPaC samplers –in parallel with the nucleopore samplers. The autopilot will be set to protrude a GPaC sampler after stabilizing at a set altitude for a set amount of time. This will allow sampling on a first substrate. The sampling holder will then retract back into its cover. The autopilot will take the UAV to a second, lower, set altitude at which point the second GPaC sampler will be activated, allowing sampling on the second substrate.
SEM/EDX analysis will be performed on the filters, delivering 2D size and shape of the particles along with an average elemental composition (elements heavier than oxygen) for each particle, as long as the material is not (too) volatile. Size range typically covered: larger than 400 nm –possibility to lower the limit to 200 or 100nm (increased analysis time). A minimum of 1500 particles to be analyzed for each sample.