A new multicopter-based unmanned aerial system for pollen and spores collection in the atmospheric boundary layer
Abstract. The application of a new particle collection system (PCS) developed in-house
and operated on board a commercially available multicopter unmanned aerial vehicle
(UAV) is presented as a new unmanned aerial system (UAS) approach for in situ
measurement of the concentration of aerosol particles such as pollen grains
and spores in the atmospheric boundary layer (ABL). A newly developed
impactor is used for high-efficiency particle extraction on board the
multicopter UAV. An airflow volume of 0.2  m3  min −1 through the
impactor is provided by a battery-powered blower and measured with an on-board
mass flow sensor. A bell-mouth-shaped air inlet of the PCS is arranged and
oriented on the multicopter UAV to provide substantial isokinetic sampling
conditions by advantageously using the airflow pattern generated by the
propellers of the multicopter UAV. More than 30 aerosol particle collection flights were carried out near
Tubingen in March 2017 at altitudes of up to 300  m above ground
level (a.g.l.), each with a sampled air volume of 2  m3 . Pollen
grains and spores of various genera, as well as large ( >20 µ m)
opaque particles and fine dust particles, were collected, and specific
concentrations of up to 100 particles per m3 were determined by
visual microscopic analysis. The pollen concentration values measured with
the new UAS match well with the pollen concentration data published by the
Stiftung Deutscher Polleninformationsdienst (PID) and by MeteoSwiss. A
major advantage of the new multicopter-based UAS is the possibility of the
identification of collected aerosol particles and the measurement of their
concentration with high temporal and spatial resolutions, which can be used
inter alia to improve the database for modelling the propagation of aerosol
particles in the ABL.