Our methodology

We use the following methodology to provide information and data of the highest integrity:


We write articles primarily using the original research done in our lab as well as from first-hand observations and experiences. When we use third-party resources, we provide citations and credits.

Air sampling:

  1. We have five Allergenco MK-3 air samplers that we use extensively year-round. Our base location is Burlingame, California, but we do mobile air sampling in other cities like San Francisco and Sunnyvale.
  2. We generally do air sampling from 8:00 am to 6:00 pm on a weekly basis, but often run samplers for full 24 hours to study the peaks and valleys of pollen release.
  3. Our lab is equipped with an Olympus compund microscope with a camera to study the air samples. We look at the entire slide as opposed to the standard practice of looking only at a partial sample.
  4. To correctly identify pollen, apart from using standard keys, we harvest pollen from local trees to create reference slides. For example, if we get pollen that looks like Alder, but we are not sure, we go out looking for Alder trees in the neighborhood, confirm that they are blooming, and then bring their pollen to the lab to match with what was caught in the air-sampler. (Read: When does alder (Alnus) release pollen?)

Pollen reports:

  1. We use simple-to-follow plants blooming cycles relative to their peak pollen days. That is where they are in comparison to their peak pollen load. For example, 90% means the species is near its peak and 10% means the pollen season for the tree is just starting out or about to complete. In contrast, other sites use the designations “High” “Medium” and “Low”, which are confusing because they are statistical markers of academic interest and have no meaning for the allergy sufferer. For example, “low” does not imply that chances of getting symptoms are low for an allergy sufferer. It just means a pollen counting station captured a lower number of pollen relative to all other pollen counting stations.
  2. When in doubt, we err on the side of caution and overestimate the presence of pollen in the air.
    1. Eample-1: In one of our early-August sampling, we did not catch any Chinese elm pollen in our air sampler in Burlingame. But, the visual inspection of nearby trees clearly showed early blooms. We brought back the flowers to our lab to confirm that the tree was indeed releasing pollen. In our report, we announce Chinese elm at 10% even though our air-sampler did not catch any pollen. Although rare, every once in a while, the wind blows a certain way that the pollen from certain trees does not get to our air samplers. In cases like that, we rely on the visual inspection of the plants.
    2. Example-2: Sometimes, when it rains, our air samplers do not catch any pollen. Although technically there are no pollen in the air at the time of air sampling, we know that it is only a temporary respite. Instead of declaring pollen as absent, we make an estimation of which pollen would be in the air if it was not raining. Because we know that the pollen would soon be in the air as soon as the conditions dry out. To estimate, we use previous week’s and previous year’s air-sampling results, as well as rely on the visual inspections of the trees.

Tree identification:

  1. We use the local city resources to locate trees by their scientific names in the local parks and communities (e.g. Botanical garden at the Golden Gate park in San Francisco). We take photos, compare with other online resources and books to validate, then pick the most recognizable traits to write our tree identification articles.
  2. We confirm the tree’s genus by bringing its pollen back to our lab and identifying it under the microscope.

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