Spieksma.
1999. This study showed an overall
similarity between airborne birch pollen grains and birch allergen. Small
quantities of allergen were detected when no pollen was registered. The mechanism
of allergen release in the paucimicronic sizes is not fully elucidated. The
authors agree that there is a need for more accurate assessment of airborne
allergen levels. They go on to state that until techniques for continuous
monitoring are more widely available, pollen counts provide a sufficiently
reliable surrogate.