A technique for collecting airborne particulate in which the sampling device has a
efficiency of unity for all sizes of particles in sampled air, regardless of wind
velocity and direction of the instrument. The air stream entering the collector has
a velocity (speed and direction) equal to that of the air in the gas stream just ahead
of the sampling port of the collector.
PAC, 1990, 62, 2167
(Glossary of atmospheric chemistry terms (Recommendations 1990))
on page 2198
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. https://doi.org/10.1351/goldbook