A history of pollen mapping and surveillance: The relations between natural history and clinical allergy

Durham himself pointed to the invisible storm of ragweed pollen located in the heartland of America, where agricultural practices that depleted soil and facilitated the spread of pioneer species like ragweed had become the subject of intense government and ecologic investigation as the Dust Bowl gripped the nation in a major agricultural and economic crisis (Fig 2).21 The recent report by the Harvard Medical School's Center for Health and the Global Environment documenting the role of increasing CO2 levels in promoting higher pollen production among opportunistic weeds and trees like ragweed, maples, birches, and poplars, and its possible effect on urban dwellers with allergy and asthma, highlights the value such aerobiological studies have played and continue to play in the understanding, prevention, and treatment of allergic disease.22 I am grateful to Dr Sheldon Cohen for his generosity in sharing with me his invaluable knowledge of the historical development of allergy as a clinical field.