This 19-20μm size ragweed pollen is a short type, botanical named Ambrosia artemisiifolia.
It is collected under a vacuum method and exceeds identity and purity by microscopic identification. It contains less than 0.1% contamination with foreign pollens or molds. Plant parts do not exceed 5% for anemophilous (wind pollinated) pollen or 12% for entomophilous (insect pollinated) pollen.