Our National Parks as Ragweed Hay Fever Refuges

Abstract

The accompanying tabular data on the ragweed pollen hazards in the national parks were secured over a period of thirteen years, during which I made field studies and carried out routine atmospheric pollen tests for one or more seasons in each of the parks and areas herein listed, except as noted. Most of the atmospheric tests have been made by the standard technic recommended by the Aero-Allergen Council of the American Academy of Allergy.1 The figures for "days of high incidence" refer to the average number of days per season when the ragweed pollen concentration reached or exceeded 25 pollen granules per cubic yard of air. "Maximum atmospheric concentration" refers to the highest number of ragweed pollen granules per cubic yard of air during any one twenty-four hour period. A "seasonal total" is the cumulative figure obtained by adding the number of ragweed pollen granules per cubic yard for each day throughout the season. The "index" figure is an arbitrary rating based on the three factors : average length of season, maximum concentration and average seasonal total.2 Areas with an index rating of 10 or more cannot be recommended as suitable for those seeking relief from ragweed hay fever. Preference should be given to parks with indexes less than 5. These may be rated from "fair" to "good." Those areas with indexes less than 1 are excellent ragweed refuges unless heavily infested with sagebrush.