I'm pediatrician and allergist in Korea. My interests are in pollen allergies and the correlation between pollen counts and allergic symptoms. I'm asking the evidence supporting four grades (Low/mod/high/very high) of NAB scale. What is the criteria classifying grades of allergic risk?


Thank you for your inquiry.

I am referring your inquiry to Dr. Warren Filley, who is chairman of the Aeroallergen Committee of the Academy. As soon as I receive a response from Dr. Filley, I will forward it to you.

Thank you again for your inquiry.

Phil Lieberman, M.D.

We have received a response from Dr. Warren Filley. Thank you again for your inquiry and we hope this response is helpful to you.

Phil Lieberman, M.D.

Response from Dr. Warren Filley:
I have an answer but probably not the one that Dr Kim wants. The scale of low/mod/high/very high was established back in the 1990's the last time I was chair of the Aerobiology committee. I talked to Estelle Levetin (who finished as chair in 2012) and she remembers as I do that this was based on statistical analysis and not on clinical symptoms. At the time Harriet Burge (who's lab at Michigan did all of our data collection and storage) took the raw data from all certified sites at the time and via statistical analysis created a numerical average of each pollen/mold and then devised the low to very high scale. It is not related to symptom scores per say.

There was some data presented from Mary Jelks regarding levels of specific allergens like ragweed and grass which were in the literature prior to the 1990's suggestive of provoking allergic reactions. That data was taken into consideration by Harriet but still the levels are solely numerical calculations without hard scientific data.

We have changed the wording on our website to reflect the fact that the ranges are based on ecological measurements and not on health effects. At one point in the past 10 years some people had tried to use our mold levels to prove there were negative health effects and some of these cases were going to trial. It was at that time that we took the suggestion of symptoms off the website.

I am not familiar with the allergens of Korea but have had some exposure to those in Japan. They have about a dozen significant allergens, many of which are grasses. OF course Cryptomeria japonica is their most allergenic plant and is found throughout the country in large forests. If the doctor is interested he can develop a counting station patterned after our certified stations and try to correlate his counts with patient symptoms in a prospective scientific format. This may be very helpful to his patients and the allergy community in general.

Warren Filley

Close-up of pine tree branches in Winter Close-up of pine tree branches in Winter