Typically, the pollen present in a mix of such low numbers does not present a source for allergy concerns. Pollen.com lists this as a pollen type only when overall pollen levels are extremely low.
Trace amounts of pollen can be found in air samples in most locations, despite the likelihood that no allergenic plants are actually actively producing pollen locally. This typically occurs during the winter months, after the fall season has ended, and before the spring tree season has started. This can also occur in the spring when trees begin pollinating in spurts that may have been missed by pollen counting samplers not yet on full-time schedules for the season. When there are no local sources actually pollinating, pollen may be resuspended into the air from the ground, and other surfaces such as tree branches, blades of grass, buildings, or roadways. Contents of the mix of pollen can be any pollen type that was in the air in higher numbers in the season, pollen from previous years or even pollen which has been transported long distances through the upper atmosphere.
Pollen grains may be recognizable as common types seen throughout other, heavier parts of they year. However, they may also be broken and unidentifiable.
The shaded areas on the map indicates where the genus has been observed in the United States.
Enter a full or partial species name to find more information on one of over 1,200 potentially allergenic plants.
For example, you can find chenopods searching on "cheno"